1 features ? 8-bit avr ? core with 83 ns instruction cycle time ? 16k bytes rom program memory ? 512 bytes sram ? 32 x 8 general purpose working registers ? 20 programmable i/o port pins ? programmable serial uart ? spi serial interface ? one 8-bit timer/counter with separate prescaler ? one 16-bit timer/counter with separate prescaler ? external and internal interrupt sources ? programmable watchdog timer with on-chip oscillator ? bus-or self-powered usb hub with four downstream ports ? one attached function port with three endpoints ? programmable 6/12 mhz oscillator with pll ? on-chip 3.3v supply for usb ? 42-pin sdip and 48-lead tqfp packages overview the atmel AT43USB321 is a single-chip microcontroller based usb hub with an embedded function and a 16k byte masked rom. the usb hub has five downstream ports, one of which is permanently attached. internally the at43320 consists of a usb hub and function interface, a hub repeater, and a high-performance, efficient 8-bit risc microcontroller. the hub and peripheral device controller function is imple- mented in the microcontollers firmware. to the usb host, the embedded function appears as an attached port of the hub with its own device address and endpoints. the AT43USB321 can also be configured as a usb function without the hub. the usb hardware block consists of a usb transceiver, sie, hub repeater, endpoint controllers, and an interface to the microcontroller. the usb hardware interfaces to the usb host at the transaction level. the cpu of the microcontroller is based on the atmel avr microcontroller. the avr architecture was developed to be programmed in c efficiently and with maximum performance. full-speed usb hub/function microcontroller AT43USB321 rev. 1442aC08/99
AT43USB321 2 figure 1. AT43USB321 block diagram development support the at4usb321 uses the same program and development tools as the atmel avr microcontrollers including: c com- pilers, macro assemblers, program debuggers/simulators, in-circuit emulators. the AT43USB321 is binary compatible with the at43320 and the two share the same develop- ment kit, which includes firmware source code for the most common usb applications. applications the attached diagram shows an application of the AT43USB321 in a monitor as a hub with two embedded functions: a monitor display controller and ir receiver. the number of external downstream ports of the hub is pro- grammable from one to four. the hub can be self-powered or bus-powered. in most cases, hubs in the monitors will be self-powered because of the readily availability of the power supply and its more versatility. in this example, the AT43USB321 interfaces to the moni- tor's microcontroller, the host microcontroller, through an i 2 c serial bus that supports two way communications such as ddc2bi. the firmware inside the AT43USB321 acts as the translator between the host system and the host micro- controller. this function can be performed without any modification in the host microcontroller's firmware resulting in a very flexible way of adding usb capability in any moni- tor. the ir receiver function is also implemented in firmware also and can support any consumer type ir proto- col that uses a frequency in the range of up to 52 khz. hub and device controller general purpose io port4 port3 port2 port1 lft osc1 osc2 6/12m dp0 dm0 pa[0:7] pb[0:7] pd0/rxd pd1/txd pd2/int0 pd3/int1 cext vcc vss dp4 dm4 dp3 dm3 dp2 dm2 dp1 dm1 ovc pwr rst osc & pll serial interface engine hub repeater
AT43USB321 3 figure 2. hub/monitor/ir chip application remote ir unit ir xcvr ir xcvr hub/monitor/ir chip upstream port downstream ports i c /uart monitor c to usb host to usb devices 2
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