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AT48801
Features
* * * * * * * * *
Compatible with MCS-51TM Products 8K bytes of On-Board Program Memory Fully Static Operation: 0 Hz to 16 MHz 256 x 8 Bit Internal RAM 32 Programmable I/O Lines Three 16 Bit Timer/Counters Eight Interrupt Sources Programmable Serial Channel Low Power Idle and Power Down Modes
Description
The AT48801 is a low-power, high-performance CMOS 8 bit microcomputer with 8K bytes on-board program memory. The device is compatible with the industry standard 80C51 and 80C52 instruction set and pinout. The Atmel AT48801 is a powerful microcomputer which provides a highly flexible and cost effective solution to spread-spectrum applications. The AT48801 provides the following standard features: 8K bytes of program memory, 256-bytes of RAM, 32 I/O lines, three 16 bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. In addition, the AT48801 is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port, and interrupt system to continue functioning. The Power Down Mode saves the RAM contents but freezes the oscillator, disabling all other chip functions until the next hardware reset.
8 Bit SpreadSpectrum Microcontroller Preliminary
Pin Configuration
PQFP
0629A
1-1
Block Diagram
1-2
AT48801
AT48801
Pin Description
VCC Supply voltage. GND Ground. Port 0 Port 0 is an 8 bit open drain bidirectional I/O port. As an output port, each pin can sink eight TTL inputs. When 1s are written to port 0 pins, the pins can be used as high-impedance inputs. Port 0 can also be configured to be the multiplexed low-order address/data bus during accesses to external program and data memory. In this mode, P0 has internal pullups. Port 1 Port 1 is an 8 bit bidirectional I/O port with internal pullups. The Port 1 output buffers can sink/source four TTL inputs. When 1s are written to Port 1 pins, they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 1 pins that are externally being pulled low will source current (IIL) because of the internal pullups. In addition, P1.0 and P1.1 can be configured to be the timer/counter 2 external count input (P1.0/T2) and the timer/counter 2 trigger input (P1.1/T2EX), respectively, as shown in the following table. Port Pin P1.0 P1.1 Port 2 Port 2 is an 8 bit bidirectional I/O port with internal pullups. The Port 2 output buffers can sink/source four TTL inputs. When 1s are written to Port 2 pins, they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 2 pins that are externally being pulled low will source current (IIL) because of the internal pullups. Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use 16 bit addresses (MOVX @ DPTR). In this application, Port 2 uses strong internal pullups when emitting 1s. During accesses to external data memory that use 8 bit addresses (MOVX @ RI), Port 2 emits the contents of the P2 Special Function Register. Port 3 Port 3 is an 8 bit bidirectional I/O port with internal pullups. The Port 3 output buffers can sink/source four TTL inputs. When 1s are written to Port 3 pins, they are pulled high by Alternate Functions T2 (external count input to Timer/Counter 2), clock-out T2EX (Timer/Counter 2 capture/reload trigger and direction control) RST Reset input. A high on this pin for two machine cycles while the oscillator is running resets the device. ALE Address Latch Enable is an output pulse for latching the low byte of the address during accesses to external memory. In normal operation, ALE is emitted at a constant rate of 1/6 the oscillator frequency and may be used for external timing or clocking purposes. Note, however, that one ALE pulse is skipped during each access to external data memory. If desired, ALE operation can be disabled by setting bit 0 of SFR location 8EH. With the bit set, ALE is active only during a MOVX or MOVC instruction. Otherwise, the pin is weakly pulled high. Setting the ALE-disable bit has no effect if the microcrontroller is in external execution mode. PSEN Program Store Enable is the read strobe to external program memory. When the AT48801 is executing code from external program memory, PSEN is activated twice each machine cycle, except that two PSEN activations are skipped during each access to external data memory. EA External Access Enable. EA must be strapped to GND in order to enable the device to fetch code from external program memory locations starting at 0000H up to FFFFH. Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset. EA should be strapped to VCC for internal program executions. (continued) Port Pin P3.0 P3.1 P3.2 P3.3 P3.4 P3.5 P3.6 P3.7 Alternate Functions RXD (serial input port) TXD (serial output port) INT0 (external interrupt 0) INT1 (external interrupt 1) T0 (timer 0 external input) T1 (timer 1 external input) WR (external data memory write strobe) RD (external data memory read strobe) the internal pullups and can be used as inputs. As inputs, Port 3 pins that are externally being pulled low will source current (IIL) because of the pullups. Port 3 also serves the functions of various special features of the AT89C51, as shown in the following table.
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Pin Description (Continued)
XTAL1 Input to the inverting oscillator amplifier and input to the internal clock operating circuit. XTAL2 Output from the inverting oscillator amplifier.
Note that not all of the addresses are occupied, and unoccupied addresses may not be implemented on the chip. Read accesses to these addresses will in general return random data, and write accesses will have an indeterminate effect. User software should not write 1s to these unlisted locations, since they may be used in future products to invoke new features. In that case, the reset or inactive values of the new bits will always be 0. Timer 2 Registers Control and status bits are contained in registers T2CON (shown in Table 2) and T2MOD (shown in Table 4) for Timer 2. The register pair
Special Function Registers
A map of the on-chip memory area called the Special Function Register (SFR) space is shown in Table 1.
(continued)
Table 1. AT48801 SFR Map and Reset Values 0F8H 0F0H 0E8H 0E0H 0D8H 0D0H 0C8H 0C0H 0B8H 0B0H 0A8H 0A0H 98H 90H 88H 80H IP XX000000 P3 11111111 IE 0X000000 P2 11111111 SCON 00000000 P1 11111111 TCON 00000000 P0 11111111 TMOD 00000000 SP 00000111 TL0 00000000 DPL 00000000 TL1 00000000 DPH 00000000 TH0 00000000 TH1 00000000 PCON 0XXX0000 SBUF XXXXXXXX PSW 00000000 T2CON 00000000 T2MOD XXXXXX00 RCAP2L 00000000 RCAP2H 00000000 TL2 00000000 TH2 00000000 ACC 00000000 B 00000000 0FFH 0F7H 0EFH 0E7H 0DFH 0D7H 0CFH 0C7H 0BFH 0B7H 0AFH 0A7H 9FH 97H 8FH 87H
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AT48801
AT48801
Table 2. T2CON--Timer/Counter 2 Control Register T2CON Address = 0C8H Bit Addressable TF2 Bit Symbol TF2 EXF2 7 EXF2 6 Function Timer 2 overflow flag set by a Timer 2 overflow and must be cleared by software. TF2 will not be set when either RCLK = 1 or TCLK = 1. Timer 2 external flag set when either a capture or reload is caused by a negative transition on T2EX and EXEN2 = 1. When Timer 2 interrupt is enabled, EXF2 = 1 will cause the CPU to vector to the Timer 2 interrupt routine. EXF2 must be cleared by software. EXF2 does not cause an interrupt in up/down counter mode (DCEN = 1). Receive clock enable. When set, causes the serial port to use Timer 2 overflow pulses for its receive clock in serial port Modes 1 and 3. RCLK = 0 causes Timer 1 overflow to be used for the receive clock. Transmit clock enable. When set, causes the serial port to use Timer 2 overflow pulses for its transmit clock in serial port Modes 1 and 3. TCLK = 0 causes Timer 1 overflows to be used for the transmit clock. Timer 2 external enable. When set, allows a capture or reload to occur as a result of a negative transition on T2EX if Timer 2 is not being used to clock the serial port. EXEN2 = 0 causes Timer 2 to ignore events at T2EX. Start/Stop control for Timer 2. TR2 = 1 starts the timer. Timer or counter select for Timer 2. C/T2 = 0 for timer function. C/T2 = 1 for external event counter (falling edge triggered). Capture/Reload select. CP/RL2 = 1 causes captures to occur on negative transitions at T2EX if EXEN2 = 1. CP/RL2 = 0 causes automatic reloads to occur when Timer 2 overflows or negative transitions occur at T2EX when EXEN2 = 1. When either RCLK or TCLK = 1, this bit is ignored and the timer is forced to auto-reload on Timer 2 overflow. When an instruction accesses an internal location above address 7FH, the address mode used in the instruction specifies whether the CPU accesses the upper 128-bytes of RAM or the SFR space. Instructions that use direct addressing access SFR space. For example, the following direct addressing instruction accesses the SFR at location 0A0H (which is P2). MOV 0A0H, #data Instructions that use indirect addressing access the upper 128-bytes of RAM. For example, the following indirect addressing instruction, where R0 contains 0A0H, accesses the data byte at address 0A0H, rather than P2 (whose address is 0A0H). (continued) RCLK 5 TCLK 4 EXEN2 3 TR2 2 C/T2 1 CP/RL2 0 Reset Value = 0000 0000B
RCLK
TCLK
EXEN2
TR2 C/T2 CP/RL2
Special Function Registers (Continued)
(RCAP2H, RCAP2L) are the Capture/Reload registers for Timer 2 in 16 bit capture mode or 16 bit auto-reload mode. Interrupt Registers The individual interrupt enable bits are in the IE register. Two priorities can be set for each of the six interrupt sources in the IP register.
Data Memory
The AT48801 implements 256-bytes of on-chip RAM. The upper 128-bytes occupy a parallel address space to the Special Function Registers. That means the upper 128bytes have the same addresses as the SFR space but are physically separate from SFR space.
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Data Memory (Continued)
MOV @R0, #data Note that stack operations are examples of indirect addressing, so the upper 128-bytes of data RAM are available as stack space. cillator frequency. To ensure that a given level is sampled at least once before it changes, the level should be held for at least one full machine cycle. Table 3. Timer 2 Operating Modes
RCLK + TCLK 0 0 1 CP/RL2 0 1 X X TR2 1 1 1 0 MODE 16 Bit Auto-Reload 16 Bit Capture Baud Rate Generator (Off)
Timer 0 and 1
Timer 0 and Timer 1 in the AT48801 operate the same way as Timer 0 and Timer 1 in the AT89C51.
Timer 2
Timer 2 is a 16 bit Timer/Counter that can operate as either a timer or an event counter. The type of operation is selected by bit C/T2 in the SFR T2CON (shown in Table 2). Timer 2 has three operating modes: capture, auto-reload (up or down counting), and baud rate generator. The modes are selected by bits in T2CON, as shown in Table 3. Timer 2 consists of two 8 bit registers, TH2 and TL2. In the Timer function, the TL2 register is incremented every machine cycle. Since a machine cycle consists of 12 oscillator periods, the count rate is 1/12 of the oscillator frequency. In the Counter function, the register is incremented in response to a l-to-0 transition at its corresponding external input pin, T2. In this function, the external input is sampled during S5P2 of every machine cycle. When the samples show a high in one cycle and a low in the next cycle, the count is incremented. The new count value appears in the register during S3P1 of the cycle following the one in which the transition was detected. Since two machine cycles (24 oscillator periods) are required to recognize a 1to-0 transition, the maximum count rate is 1/24 of the osFigure 1. Timer 2 in Capture Mode
X
Capture Mode
In the capture mode, two options are selected by bit EXEN2 in T2CON. If EXEN2 = 0, Timer 2 is a 16 bit timer or counter which upon overflow sets bit TF2 in T2CON. This bit can then be used to generate an interrupt. If EXEN2 = 1, Timer 2 performs the same operation, but a l-to-0 transition at external input T2EX also causes the current value in TH2 and TL2 to be captured into RCAP2H and RCAP2L, respectively. In addition, the transition at T2EX causes bit EXF2 in T2CON to be set. The EXF2 bit, like TF2, can generate an interrupt. The capture mode is illustrated in Figure 1.
Auto-Reload (Up or Down Counter)
Timer 2 can be programmed to count up or down when configured in its 16 bit auto-reload mode. This feature is invoked by the DCEN (Down Counter Enable) bit located in the SFR T2MOD (see Table 4). Upon reset, the DCEN bit is set to 0 so that timer 2 will default to count up. When DCEN is set, Timer 2 can count up or down, depending on the value of the T2EX pin. (continued)
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AT48801
AT48801
Auto-Reload (Up or Down Counter) (Continued)
Figure 2 shows Timer 2 automatically counting up when DCEN = 0. In this mode, two options are selected by bit EXEN2 in T2CON. If EXEN2 = 0, Timer 2 counts up to 0FFFFH and then sets the TF2 bit upon overflow. The overflow also causes the timer registers to be reloaded with the 16 bit value in RCAP2H and RCAP2L. The values in RCAP2H and RCAP2L are preset by software. If EXEN2 = 1, a 16 bit reload can be triggered either by an overflow or by a l-to-0 transition at external input T2EX. This transition also sets the EXF2 bit. Both the TF2 and EXF2 bits can generate an interrupt if enabled. Setting the DCEN bit enables Timer 2 to count up or down, as shown in Figure 3. In this mode, the T2EX pin controls the direction of the count. A logic 1 at T2EX makes Timer Figure 2. Timer 2 Auto Reload Mode (DCEN = 0) 2 count up. The timer will overflow at 0FFFFH and set the TF2 bit. This overflow also causes the 16 bit value in RCAP2H and RCAP2L to be reloaded into the timer registers, TH2 and TL2, respectively. A logic 0 at T2EX makes Timer 2 count down. The timer underflows when TH2 and TL2 equal the values stored in RCAP2H and RCAP2L. The underflow sets the TF2 bit and causes 0FFFFH to be reloaded into the timer registers. The EXF2 bit toggles whenever Timer 2 overflows or underflows and can be used as a 17th bit of resolution. In this operating mode, EXF2 does not flag an interrupt.
Table 4. T2MOD--Timer 2 Mode Control Register T2MOD Address = 0C9H Not Bit Addressable -- Bit Symbol -- T2OE DCEN 7 -- 6 Function Not implemented, reserved for future use. Timer 2 Output Enable bit. When set, this bit allows Timer 2 to be configured as an up/down counter. -- 5 -- 4 -- 3 -- 2 T2OE 1 DCEN 0 Reset Value = XXXX XX00B
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Figure 3. Timer 2 Auto Reload Mode (DCEN = 1)
Figure 4. Timer 2 in Baud Rate Generator Mode
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AT48801
AT48801
Baud Rate Generator
Timer 2 is selected as the baud rate generator by setting TCLK and/or RCLK in T2CON (Table 2). Note that the baud rates for transmit and receive can be different if Timer 2 is used for the receiver or transmitter and Timer 1 is used for the other function. Setting RCLK and/or TCLK puts Timer 2 into its baud rate generator mode, as shown in Figure 4. The baud rate generator mode is similar to the auto-reload mode, in that a rollover in TH2 causes the Timer 2 registers to be reloaded with the 16 bit value in registers RCAP2H and RCAP2L, which are preset by software. The baud rates in Modes l and 3 are determined by Timer 2's overflow rate according to the following equation.
Modes 1 and 3 Oscillator Frequency = Baud Rate 32 x [65536 - (RCAP2H, RCAP2L)]
where (RCAP2H, RCAP2L) is the content of RCAP2H and RCAP2L taken as a 16 bit unsigned integer. Timer 2 as a baud rate generator is shown in Figure 4. This figure is valid only if RCLK or TCLK = 1 in T2CON. Note that a rollover in TH2 does not set TF2 and will not generate an interrupt. Note too, that if EXEN2 is set, a l-to0 transition in T2EX will set EXF2 but will not cause a reload from (RCAP2H, RCAP2L) to (TH2, TL2). Thus when Timer 2 is in use as a baud rate generator, T2EX can be used as an extra external interrupt. Note that when Timer 2 is running (TR2 = 1) as a timer in the baud rate generator mode, TH2 or TL2 should not be read from or written to. Under these conditions, the Timer is incremented every state time, and the results of a read or write may not be accurate. The RCAP2 registers may be read but should not be written to, because a write might overlap a reload and cause write and/or reload errors. The timer should be turned off (clear TR2) before accessing the Timer 2 or RCAP2 registers.
Modes 1 and 3 Baud Rates =
Timer 2 Overflow Rate 16
The Timer can be configured for either timer or counter operation. In most applications, it is configured for timer operation (CP/T2 = 0). The timer operation is different for Timer 2 when it is used as a baud rate generator. Normally, as a timer, it increments every machine cycle (at 1/12 the oscillator frequency). As a baud rate generator, however, it increments every state time (at 1/2 the oscillator frequency). The baud rate formula is given below.
Figure 5. Timer 2 in Clock-Out Mode
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Programmable Clock Out
A 50% duty cycle clock can be programmed to come out on P1.0, as shown in Figure 5. This pin, besides being a regular I/0 pin, has two alternate functions. It can be programmed to input the external clock for Timer/Counter 2 or to output a 50% duty cycle clock ranging from 61 Hz to 4 MHz at a 16 MHz operating frequency. To configure the Timer/Counter 2 as a clock generator, bit C/T2 ( T 2 C O N . 1 ) m u s t b e c l e a r e d a n d b i t T2 O E (T2MOD.1) must be set. Bit TR2 (T2CON.2) starts and stops the timer. The clock-out frequency depends on the oscillator frequency and the reload value of Timer 2 capture registers (RCAP2H, RCAP2L), as shown in the following equation.
Clock-Out Frequency = Oscillator Frequency 4 x [65536 - (RCAP2H, RCAP2L)]
Interrupts
The AT48801 has a total of six interrupt vectors: two external interrupts (INT0 and INT1), three timer interrupts (Timers 0, 1, and 2), and the serial port interrupt. These interrupts are all shown in Figure 6. Each of these interrupt sources can be individually enabled or disabled by setting or clearing a bit in Special Function Register IE. IE also contains a global disable bit, EA, which disables all interrupts at once. Note that Table 5 shows that bit position IE.6 is unimplemented. In the AT89C51, bit position IE.5 is also unimplemented. User software should not write 1s to these bit positions, since they may be used in future AT89 products. Timer 2 interrupt is generated by the logical OR of bits TF2 and EXF2 in register T2CON. Neither of these flags is cleared by hardware when the service routine is vectored (continued) Table 5. Interrupt Enable (IE) Register
(MSB) (LSB)
In the clock-out mode, Timer 2 roll-overs will not generate an interrupt. This behavior is similar to when Timer 2 is used as a baud-rate generator. It is possible to use Timer 2 as a baud-rate generator and a clock generator simultaneously. Note, however, that the baud-rate and clock-out frequencies cannot be determined independently from one another since they both use RCAP2H and RCAP2L.
EA
--
ET2 ES
ET1 EX1 ET0 EX0
UART
The UART in the AT48801 operates the same way as the UART in the AT89C51. Figure 6. Interrupt Sources EA
Enable Bit = 1 enables the interrupt. Enable Bit = 0 disables the interrupt. Symbol Position Function Disables all interrupts. If EA = 0, no interrupt is acknowledged. If EA = 1, each interrupt source is individually enabled or disabled by setting or clearing its enable bit. Reserved. Timer 2 interrupt enable bit. Serial Port interrupt enable bit. Timer 1 interrupt enable bit. External interrupt 1 enable bit. Timer 0 interrupt enable bit. External interrupt 0 enable bit.
IE.7
-- ET2 ES ET1 EX1 ET0 EX0
IE.6 IE.5 IE.4 IE.3 IE.2 IE.1 IE.0
User software should never write 1s to unimplemented bits, because they may be used in future AT89 products.
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AT48801
AT48801
Interrupts (Continued)
to. In fact, the service routine may have to determine whether it was TF2 or EXF2 that generated the interrupt, and that bit will have to be cleared in software. The Timer 0 and Timer 1 flags, TF0 and TFI, are set at S5P2 of the cycle in which the timers overflow. The values are then polled by the circuitry in the next cycle. However, the Timer 2 flag, TF2, is set at S2P2 and is polled in the same cycle in which the timer overflows.
Power Down Mode
In the power down mode, the oscillator is stopped, and the instruction that invokes power down is the last instruction executed. The on-chip RAM and Special Function Registers retain their values until the power down mode is terminated. The only exit from power down is a hardware reset. Reset redefines the SFRs but does not change the onchip RAM. The reset should not be activated before VCC is restored to its normal operating level and must be held active long enough to allow the oscillator to restart and stabilize. Figure 7. Oscillator Connections
Oscillator Characteristics
XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier that can be configured for use as an on-chip oscillator, as shown in Figure 7. Either a quartz crystal or ceramic resonator may be used. To drive the device from an external clock source, XTAL2 should be left unconnected while XTAL1 is driven, as shown in Figure 8. There are no requirements on the duty cycle of the external clock signal, since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage high and low time specifications must be observed.
Idle Mode
In idle mode, the CPU puts itself to sleep while all the onchip peripherals remain active. The mode is invoked by software. The content of the on-chip RAM and all the special functions registers remain unchanged during this mode. The idle mode can be terminated by any enabled interrupt or by a hardware reset. Note that when idle mode is terminated by a hardware reset, the device normally resumes program execution from where it left off, up to two machine cycles before the internal reset algorithm takes control. On-chip hardware inhibits access to internal RAM in this event, but access to the port pins is not inhibited. To eliminate the possibility of an unexpected write to a port pin when idle mode is terminated by a reset, the instruction following the one that invokes idle mode should not write to a port pin or to external memory.
Notes: C1, C2 = 30 pF 10 pF for Crystals = 40 pF 10 pF for Ceramic Resonators
Figure 8. External Clock Drive Configuration
Status of External Pins During Idle and Power Down
Mode Idle Idle Power Down Power Down Program Memory Internal External Internal External ALE 1 1 0 0 PSEN 1 1 0 0 PORT0 Data Float Data Float PORT1 Data Data Data Data PORT2 Data Address Data Data PORT3 Data Data Data Data
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Absolute Maximum Ratings*
Operating Temperature................... -55C to +125C Storage Temperature...................... -65C to +150C Voltage on Any Pin with Respect to Ground ..................... -1.0V to +7.0V Maximum Operating Voltage ............................. 6.6V DC Output Current ....................................... 15.0 mA
*NOTICE: Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DC Characteristics
The values shown in this table are valid for TA = -40C to 85C and VCC = 5.0V 20%, unless otherwise noted. Symbol
VIL VIL1 VIH VIH1 VOL VOL1 VOH
Parameter
Input Low Voltage Input Low Voltage (EA) Input High Voltage Input High Voltage Output Low Voltage (1) (Ports 1,2,3) Output Low Voltage (Port 0, ALE, PSEN)
(1)
Condition
(Except EA) (Except XTAL1, RST) (XTAL1, RST) IOL = 1.6 mA IOL = 3.2 mA
Min
-0.5 -0.5 0.2 VCC + 0.9 0.7 VCC
Max
0.2 VCC - 0.1 0.2 VCC - 0.3 VCC + 0.5 VCC + 0.5 0.45 0.45
Units
V V V V V V V V V V V V
VOH1
IOH = -60 A, VCC = 5V 10% IOH = -25 A IOH = -10 A IOH = -800 A, VCC = 5V 10% Output High Voltage (Port 0 in External Bus Mode) IOH = -300 A IOH = -80 A Output High Voltage (Ports 1,2,3, ALE, PSEN) Logical 0 Input Current (Ports 1,2,3) Logical 1 to 0 Transition Current (Ports 1,2,3) Input Leakage Current (Port 0, EA) Reset Pulldown Resistor Pin Capacitance Power Supply Current Test Freq. = 1 MHz, TA = 25C Active Mode, 12 MHz Idle Mode, 12 MHz VCC = 6V VCC = 3V VIN = 0.45V VIN = 2V 0.45 < VIN < VCC
2.4 0.75 VCC 0.9 VCC 2.4 0.75 VCC 0.9 VCC -50 -650 10 50 300 10 25 6.5 100 40
IIL ITL ILI RRST CIO ICC
A A A k pF mA mA A A
Power Down Mode (2)
Notes: 1. Under steady state (non-transient) conditions, IOL must be externally limited as follows: Maximum IOL per port pin: 10 mA Maximum IOL per 8 bit port: Port 0: 26 mA Ports 1,2, 3: 15 mA
Maximum total IOL for all output pins: 71 mA If IOL exceeds the test condition, VOL may exceed the related specification. Pins are not guaranteed to sink current greater than the listed test conditions. 2. Minimum VCC for Power Down is 2V.
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AT48801
AT48801
AC Characteristics
Under operating conditions, load capacitance for Port 0, ALE, and PSEN = 100 pF; load capacitance for all other outputs = 80 pF.
External Program and Data Memory Characteristics
12 MHz Oscillator Symbol 1/tCLCL tLHLL tAVLL tLLAX tLLIV tLLPL tPLPH tPLIV tPXIX tPXIZ tPXAV tAVIV tPLAZ tRLRH tWLWH tRLDV tRHDX tRHDZ tLLDV tAVDV tLLWL tAVWL tQVWX tQVWH tWHQX tRLAZ tWHLH Parameter Oscillator Frequency ALE Pulse Width Address Valid to ALE Low Address Hold After ALE Low ALE Low to Valid Instruction In ALE Low to PSEN Low PSEN Pulse Width PSEN Low to Valid Instruction In Input Instruction Hold After PSEN Input Instruction Float After PSEN PSEN to Address Valid Address to Valid Instruction In PSEN Low to Address Float RD Pulse Width WR Pulse Width RD Low to Valid Data In Data Hold After RD Data Float After RD ALE Low to Valid Data In Address to Valid Data In ALE Low to RD or WR Low Address to RD or WR Low Data Valid to WR Transition Data Valid to WR High Data Hold After WR RD Low to Address Float RD or WR High to ALE High 43 200 203 23 433 33 0 123 tCLCL - 20 0 97 517 585 300 3tCLCL - 50 4tCLCL - 75 tCLCL - 20 7tCLCL - 120 tCLCL - 20 0 tCLCL + 25 400 400 252 0 2tCLCL - 28 8tCLCL - 150 9tCLCL - 165 3tCLCL + 50 75 312 10 6tCLCL - 100 6tCLCL - 100 5tCLCL - 90 0 59 tCLCL - 8 5tCLCL - 55 10 43 205 145 0 tCLCL - 10 127 28 48 233 tCLCL - 13 3tCLCL - 20 3tCLCL - 45 Min Max Variable Oscillator Min 0 2tCLCL - 40 tCLCL - 13 tCLCL - 20 4tCLCL - 65 Max 16 Units
MHz ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns
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External Program Memory Read Cycle
External Data Memory Read Cycle
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AT48801
AT48801
External Data Memory Cycle
External Clock Drive Waveforms
External Clock Drive
Symbol 1/tCLCL tCLCL tCHCX tCLCX tCLCH tCHCL Parameter Oscillator Frequency Clock Period High Time Low Time Rise Time Fall Time Min 0 62.5 15 15 20 20 Max 16 Units MHz ns ns ns ns ns
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Serial Port Timing: Shift Register Mode Test Conditions
The values in this table are valid for VCC = 5.0V 20% and Load Capacitance = 80 pF. 12 MHz Osc Symbol tXLXL tQVXH tXHQX tXHDX tXHDV Parameter Serial Port Clock Cycle Time Output Data Setup to Clock Rising Edge Output Data Hold After Clock Rising Edge Input Data Hold After Clock Rising Edge Clock Rising Edge to Input Data Valid Min 1.0 700 50 0 700 Max Variable Oscillator Min 12tCLCL 10tCLCL - 133 2tCLCL - 33 0 10tCLCL - 133 Max Units s ns ns ns ns
Shift Register Mode Timing Waveforms
AC Testing Input/Output Waveforms
(1)
Float Waveforms
(1)
Note:
1. AC Inputs during testing are driven at VCC - 0.5V for a logic 1 and 0.45V for a logic 0. Timing measurements are made at VIH min. for a logic 1 and VIL max. for a logic 0.
Note:
1. For timing purposes, a port pin is no longer floating when a 100 mV change from load voltage occurs. A port pin begins to float when a 100 mV change from the loaded VOH/VOL level occurs.
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AT48801
AT48801
Ordering Information
Speed (MHz) 16 Power Supply 5V 20% Ordering Code AT48801-16QC AT48801-16QI Package 44Q 44Q Operation Range Commercial (0C to 70C) Industrial (-40C to 85C)
Package Type
44Q
44 Lead, Plastic Gull Wing Quad Flatpack (PQFP)
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