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em84502 ps/2 mouse controller 1 * this specification are subject to be changed without notice. 6.18.1998 em84502 ps/2 mouse controller general description the em84502 mouse controller is specially designed to control ps/2 mouse device.this single chip can interface three key-switches and four photo-couples direct to 8042. em84502 can receive command and echo status or data format which are compatible with ibm ps/2 mode mouse. key debouncing circuit is provided to prevent false entry and improve the accuracy. in the conventional mouse, a great number of noises are generated when the grid is partially closed or opened. these noise are usually mistaken for movement signals by conventional mouse controller and the cursor of the dispaly screen is thus moved frequently up and down or back and forth. this will consumes a great amount of energy.the em84502 ps/2 mouse controller provides noise immunity circuits to eliminate these noise in order to reduce energy consumption. features ? being compatiable with ps/2 mouse mode. ? built-in noise immunity circuit. ? low power dissipation. ? rc oscillation. ? three key-switches and four photo-couples inputs. ? both key-press and key-release debounce interval 12 ms. ? through three key-switches input, em84502 can exert seven different output. ? the motion detector of the em84502 could sense 8 m/sec maximun with 200 dpi wheels. applications ? optical mouse or pen-mouse. ? mechanical mouse or pen-mouse. ? optomechanical mouse or pen-mouse. ? mechanical track ball. ? optomechanical track ball. pin assignment * (under developed) v dd op nc nc osc.out clk data vss 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 oscr y2 y1 x2 x1 l m r em84502bp v dd op nc nc osc.out clk data vss 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 oscr y2 y1 x2 x1 l m r em84502bm* v dd op osc.out clk data vss r 1 2 3 4 5 6 7 14 13 12 11 10 9 8 oscr y2 y1 x2 x1 l m em84502ap v dd op osc.out clk data vss r 1 2 3 4 5 6 7 14 13 12 11 10 9 8 oscr y2 y1 x2 x1 l m EM84502AM
em84502 ps/2 mouse controller 2 * this specification are subject to be changed without notice. 6.18.1998 v dd power op i x, y inputs. floating : comparator input. gnd : schmitt trigger input. short to osc out : testing mode. oscout o clock output. clk i/o 8042 auxiliary port clk line. data i/o 8042 auxiliary port data line. v ss ground r i three key-switches exert seven different combinations totally. both key-pressed m and key-released signals will be sent accomplanied with horizontal and vertical l state. the status of the key-switches will be preserved, whenever the value of horizontal or vertical counters will present at data. and the debounce interval for both key-press and key-release is 12 ms. x1 i four photo-couple signals denote up, down, left, and right state. x2 during the scaning period, as long as the photo-couples change their states, the y1 value of vertical or horizontal counter will increase or decrease accordingly. y2 oscr i 30 kohm 5% pull low for 35 khz oscillation. function descriptions a) operating mode there are four operating modes in ps/2 mouse: i). reset mode: in this mode a self-test is initiated during power-on or by a reset command. after reset signal, ps/2 mouse will send: 1). completion code aa & id code 00. functional block diagram d e t e c t o r m o t i o n i m m u n it y n o i s e d e b o u n c e c o n v e r t e r d a t a d e c o d e r c o m m a n d counter timing controller data i/o system clock generator op x1 x2 y1 y2 l m r oscr osc ou t data clk symbol i/o function pin descriptions
em84502 ps/2 mouse controller 3 * this specification are subject to be changed without notice. 6.18.1998 2). set default: sampling rate: 100 reports/s non-autospeed stream mode 2 dot/count disable ii). stream mode: the maximum rate of transfer is the programmed sample rate. data report is transmitted if 1). switch is pressed 2). movement has been detect iii). remote mode: data is transmitted only in response to a read data command. iv). wrap mode: any byte of data sent by the system, except hex ec ( reset wrap mode ) or hex ff ( reset ), is returned by em84502. b). ps/2 mouse data report: i). in stream mode: a data report is sent at the end of a sample interval. ii). in remote mode: a data report is sent in response to read data command. iii). data report format: byte bit description 1 0 left button status; 1 = pressed 1 right button status; 1 = pressed 2 middle button status; 1 = pressed 3 reserve 4 x data sign; 1 = negative 5 y data sign; 1 = negative 6 x data overflow; 1 = overflow 7 y data overflow; 1 = overflow 2 0-7 x data ( d0 - d7 ) 3 0-7 y data ( d0 - d7 ) c) ps/2 mouse data transmission: i). em84502 generates the clocking signal when sending data to and receiving data from the system. ii). the system requests em84502 receive system data output by forcing the data line to an inactive level and allowing clk line to go to an active level. iii). data transmission frame:
em84502 ps/2 mouse controller 4 * this specification are subject to be changed without notice. 6.18.1998 bit function 1 start bit ( always 0 ) 2-9 data bits ( d0 - d7 ) 10 parity bit ( odd parity ) 11 stop bit ( always 1 ) iv). data output ( data from em84502 to system ): if clk is low ( inhibit status ) , data is no transmission. if clk is high and data is low ( request-to-send ), data is updated. data is received from the system and no transmission are started by em84502 until clk and data both high. if clk and data are both high, the transmission is ready. data is valid prior to the falling edge of clk and beyond the rising edge of clk. during transmission, em84502 check for line contention by checking for an inactive level on clk at intervals not to exceed 100u sec. contention occurs when the system lowers clk to inhibit em84502 output after em84502 has started a transmission. if this occurs before the rising edge of the tenth clock, em84502 internal store its data in its buffer and returns data and clk to an active level. if the contention does not occur by the tenth clock, the transmission is complete. following a transmission, the system inhibits em84502 by holding clk low until it can service the input or until the system receives a request to send a response from em84502. v). data input ( from system to em84502 ): system first check if em84502 is transmitting data. if em84502 is transmitting, the system can override the output forcing clk to an inactive level prior to the tenth clock. if em84502 transmission is beyond the tenth clock, the system receives the data. if em84502 is not transmitting or if the system choose to override the output, the system force clk to an inactive level for a period of not less than 100 m sec while preparing for output. when the system is ready to output start bit (0), it allows clk go to active level. if request-to-send is detected, em84502 clocks 11 bits. following the tenth clock em84502 checks for an active level on the data line, and if found, force data low , and clock once more. if occurs framing error, em84502 continue to clock until data is high, then clocks the line control bit and request a resend. when the system sends out a command or data transmission that requires a response, the system waits for em84502 to response before sending its next output. d). ps/2 mouse error handling: i). a resend command ( fe ) following receipt of an invalid input or any input with incorrect parity. ii). if two invalid input are received in succession, an error code of hex fc send to the system. iii). the counter accumulators are cleared after receiving any command except resend. iv). em84501 receives a resend command ( fe ), it transmit its last packet of data. v). in the stream mode resend is received by em84502 following a 3-byte data packet transmission to the system. em84502 resend the 3-byte data packet prior to clearing the counter. vi). a response is sent within 25 ms if
em84502 ps/2 mouse controller 5 * this specification are subject to be changed without notice. 6.18.1998 a). the system requires a response b). an error is detected in the transmission vii). when a command requiring a response is issued by the system ,another command should not be issue until either the response is received or 25ms has passed. e). ps/2 mouse commands description: there are 16 valid commands that transmits between the system and em84502. the fa code is always the first response to any valid input received from the system other than a set wrap mode or resend command. the following table list the commands: hex code command em84502 echo code ff reset fa,aa,00 fe resend xx,(xx,xx) f6 set default fa f5 disable fa f4 enable fa f3,xx set sampling rate fa,fa f2 read device type fa,00 f0 set remote mode fa ee set wrap mode fa ec reset wrap mode fa eb read data fa,xx,xx,xx ea set stream mode fa e9 status request fa,xx,xx,xx e8,xx set resolution fa,fa e7 set autospeed fa e6 reset autospeed fa the following describes valid commands: a). reset ( ff ) em84502 operation: i). completion the reset. ii). transmitted fa,aa,00 to the system. iii). set default: sampling rate: 100 reports/s non-autospeed stream mode 2 dots/count disable b). resend ( fe ) i). any time em84502 receives an invalid command, it returns a resend command to the system. ii). when em84502 receives a resend command, it retransmits its last packet of data. if the last packet was a resend command, it transmits the packet just prior to the resend command. iii). in stream mode, if a resend command is received by em84502 immediately following a 3-byte data packet transmission to the system.
em84502 ps/2 mouse controller 6 * this specification are subject to be changed without notice. 6.18.1998 c). set default ( f6 ) the command reinitializes all conditions to the power-on defaults. d). disable ( f5 ) this command is used in the stream mode to stop transmissions from em84502. e). enable ( f4 ) begins transmissions, if in stream mode. f). set sampling rate ( f3,xx ) in the stream mode, this command sets the sampling rate to the value indicated by byte hex xx, shown in following: second byte xx sample rate 0a 10/sec 14 20/sec 28 40/sec 3c 60/sec 50 80/sec 64 100/sec c8 200/sec g). read device type ( f2 ) em84502 always echoes fa,00 following this command. h). set remote mode ( f0 ) data value are reported only in response to a read data command. i). set wrap mode ( ee ) wrap mode remains until reset ( ff ) or reset wrap mode( ec ) is received. j). reset wrap mode ( ec ) em84502 returns to the previous mode of operation after receiving this command. k). read data ( eb ) this command is executed in either remote or stream mode. the data is transmitted even if there has been no movement since the last report or the button status is unchanged. following a read data command, the registers are cleared after a data transmission. l). set stream mode ( ea ) this command sets em84502 in stream mode. m). status request ( e9 ) when this command is issued by the system, em84502 respond with a 3-byte status report as follows: byte bit description 1 0 1 = right button pressed 1 1 = middle button pressed 2 1 = left button pressed
em84502 ps/2 mouse controller 7 * this specification are subject to be changed without notice. 6.18.1998 n). set resolution ( e8,xx ) em84502 provides four resolutions selected by the second byte of this command as follows: second byte xx resolution 00 8 dot/count 01 4 dot/count 02 2 dot/count 03 1 dot/count 3 reserved 4 0 = normal speed, 1 = autospeed 5 0 = disabled, 1 = enabled 6 0 = stream mode, 1 = remote mode 7 reserved 2 0-7 current resolution setting ( d0 - d7 ) 3 0-7 current sampling rate ( d0 - d7 ) o). set autospeed ( e7 ) at the end of a sample interval in the stream mode, the current x and y data values are converted new values. the sign bits are not involved in this conversion. the conversion is only in stream mode. the relationship between the input and output count follows: input ouput 00 11 21 33 46 59 n( 3 6 ) 2.0*n p). reset autospeed ( e6 ) this command restore normal speed. f) testing mode whenever opt is connected to osc out, the chip will enter buyer's testing mode. the x direction output signals of comparators will present to l and m pin. pressing "r" key can toggle the output from x direction to y direction. absolute maximum ratings parameter sym. ratings unit temperature under bias t opr 0~70 c storage temperature range t str -65~150 c input voltage v in -0.3~6.0 v output voltage v o -0.3~6.0 v
em84502 ps/2 mouse controller 8 * this specification are subject to be changed without notice. 6.18.1998 * all voltages in above table are compared with v ss . * all parameters in above table are tested under v dd =5v. * clk & data output gates are open drains that connect to pull up resistors. * x1, x2,y1,t2 input impedance 5.0 4.0 3.0 2.0 1.0 10.0m 0 1.0k 2.0k 3.0k 4.0k 5.0k 6.0k 7.0k 8.0k 9.0k 10.0.k 11.0k 12.0k 13.0k 14.0k volts (lin) 15.0k 16.0k max. typ. min. dc electrical characteristics (t a =25 c to 70 c) parameters sym. min. typ. max. unit operating voltage v dd 4.5 5 5.5 v operating current (no load) i op - - 1.2 ma x,x2,y1,y2 low input reference current i pl 70 - - m a x,x2,y1,y2 high input reference current i ph - - 106 m a x,x2,y1,y2 input current v pi 0.8 - 1.2 v schmitt trigger input (76 m a) x,x2,y1,y2 input current v pi 0.8 - 1.2 v comparator input (80 m a) x,x2,y1,y2 input current v pi 1.5 - 2.1 v comparator input (500 m a) clk, data postive-going vt+ 3.2 - 3.8 v threshold voltage clk, data negative-going vt - 1.2 - 1.9 v threshold voltage low input voltage, other pins vail - - 1.5 v high input voltage, other pins vaih 3.5 - - v l, m, r input current imi 16.6 - 50 m a (pull low resistor vin=5v) ps/2 mouse mode data, clk input current idc 0.56 - 1.86 ma (pull up resistor) (vin=0v) ps/2 mouse mode data, clk low output voltage vprl - - 0.4 v (iprl=-2ma) l, m, r, x1, x2, y1, y2 input leakage current iil 0 - 1.0 m a (vin=0v)
em84502 ps/2 mouse controller 9 * this specification are subject to be changed without notice. 6.18.1998 timing diagram (1) photo-couples pulse width : ac electrical characteristics (t a =0 c to 70 c) parameters sym. min. typ. max. unit oscillating frequency fosc 34.3-10% 34.3 34.3+10% khz key debounce tkd - 12 - ms rising edge crossed width fosc=35 khz tr 14.3 - - us falling edge crossed width fosc=35 khz tf 14.3 - - us mouse clk active time tmca - 42.9 - us mouse clk inactive time tmci - 42.9 - us mouse sample data from tmdc - 14.3 - us clk rising edge system clk active time tsca - 42.9 - us system clk inactive time tsci - 42.9 - us time from data transition to falling edge of clk tsdc - 14.3 - us time from rising edge of clk to data transition tscd - 28.6 - us time to mouse inhibit after the 11th clk to tpi 0 - 50 us ensure mouse does not start another transmission ps. the ac timings are measured under using 35 khz system clock signal. (2) ps/2 mouse (a) receiving data x1 (y1) x2 (y2) tr tf ???? ????????? ?? ???? ? clk data inhibit 1st clk 2nd clk 9th clk 10th clk 11th clk tmca tmci tmdc start bit bit0 -bit7 parity bit stop bit line control bit >< >< ><
em84502 ps/2 mouse controller 10 * this specification are subject to be changed without notice. 6.18.1998 (b) sending data ??????????? ????????? ?? ???? clk data 1st clk 2nd clk 10th clk 11th clk tsci tsca tscd start bit bit0 -bit7 parity bit stop bit >< >< >< tsdc >< tpi >< ???????? (r,m,l) (r,m,l) internal signal data input signal v cc data output signal ps2 mouse enable v cc data clk clk input signal v cc clk output signal ps2 mouse enable ac timing point: em84502 i/o pin equivalent circuit : r,m,l : data : clk : x1,x2,y1,y2 : 48.4 m a 39.6 m a v dd v ss output: input: x1,x2,y1,y2 pin l,m,r pin v dd -0.8 v ss +0.8 clk, data pin v dd -2.6 v ss +0.4 data, clk pin (ps/2 mouse mode) +1.6v v ss phase digital signal x1,x2,y1,y2 12.5k 80? 30k v dd v dd v dd 4 v cc - + - + 12.5k 13.2k 13.2k
em84502 ps/2 mouse controller 11 * this specification are subject to be changed without notice. 6.18.1998 application circuit 1 13 12 11 10 9 8 7 clk data ground +5v v ss op osc.dr osc.out data 4 2 14 5 6 3 dd v y2 y1 x2 x1 l m r clk 510 10 m f 510 ps/2 mouse only 30k em84501 em84502a
em84502 ps/2 mouse controller 12 * this specification are subject to be changed without notice. 6.18.1998 b j eb d e1 b1 e l l1 a a1 f c e1 1 15 (2x) 15 (4x) 5 (2x) 14 pdip min. typ. max. min. typ. max. a - .130 - - 3.302 - a1 .059 .060 .061 1.499 1.524 1.549 b - .018 - - 0.457 - b1 - .060 - - 1.524 - c - .010 - - 0.254 - d .740 .750 .760 18.796 19.050 19304 e1 .259 .260 - 6.579 6.604 - f .290 .300 .310 7.366 7.620 7.874 l - .130 - - 3.302 - l1 - .020 - - 0.506 - e - .100 - - 2.540 - eb .345 .355 .365 8.763 9.017 9.271 j 0 7.5 15 0 7.5 15 inches milimeters symbol

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