HW5soln-3750-F09 - EE 3750 HW 5 solutions 1 EE 3750...

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EE 3750 — HW 5 solutions 1 EE 3750 — Homework 5 solutions Fall 2009 1. Write an 8086 instruction sequence to initialize a 16550 UART (serial interface). Set data length to 6 bits, use 2 stop bits, use even parity, use a baud rate divisor of 480, disable the FIFO queues, and enable receiver and transmitter interrupts. Let the low port address of the 16550 be 60H. Clearly state any additional assumptions that you make. Note: In addition to Brey §11-5 on the 16550, pp. 475-481 in §12-4 deal with interrupts and the 16550. The two “memory FIFOs” in the Brey text example are part of the example only and are not part of the problems on this homework. DLL EQU 60H ; divisor latch low DLH EQU 61H ; divisor latch high LINEC EQU 63H ; line control FIFOC EQU 62H ; FIFO control INTEN EQU 61H ; interrupt enable MOV AL, 10000000B ; set up access to divisor latch ( 1xxxxxxx ) OUT LINEC, AL MOV AX, 480 ; divisor value OUT DLL, AL ; lower divisor latch MOV AL, AH OUT DLH, AL ; upper divisor latch MOV AL, 00011101B ; even parity, 6 bits data, 2 stop bits OUT LINEC, AL MOV AL, 0 ; disable FIFO ( xx000xx0 ) OUT FIFOC, AL MOV AL, 11B ; enable transmitter and receiver interrupts OUT INTEN, AL 2. Write an interrupt service routine for an 8086 to input a word of data from device DEV0 then store it in array yellow . Assume that word variable pointer holds the offset to which the next word is to be stored in yellow . The interrupt service routine should input only one word on each interrupt from DEV0; if DEV0 has already input 740 words, however, then the interrupt
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HW5soln-3750-F09 - EE 3750 HW 5 solutions 1 EE 3750...

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