PAKs and 8051s

Yamel Cuevas was good enough to share his 8051/8052/89C52 code for talking to the PAK-II (or any of the SHIFTIN/SHIFTOUT PAKs). The pak_reset routine does the initial reset required. You can use pak_send to send commands, pak_wait to wait for a response, and pak_get to read the results. Input and output are to the accumulator.

Thanks Yamel!

;Yamel Cuevas

;4/6/2001



;;Routines to interface 89c52 with PAK II math co processor.

;pak_reset pak_delay pak_send pak_get pak_wait





Sout equ P1.7 ;in/out pin on the PAK II

clk equ P1.6 ;clock pin for the PAK II

busy equ P1.5

pak_byte equ 20h ;used as temp store for transfers

p_bit0 equ 0

p_bit1 equ 1

p_bit2 equ 2

p_bit3 equ 3

p_bit4 equ 4

p_bit5 equ 5

p_bit6 equ 6

p_bit7 equ 7

Sin equ P1.4





pak_reset:

;This function resets the PAK by bringing the data line from low to high

;while the clock is high

clr Sin

lcall pak_delay

clr clk

setb clk

nop

setb Sin

nop

clr clk

lcall pak_delay

setb Sout ;set Sout as input pin

ret







pak_delay:

;appropriate half delay for clk period

mov r0, #20d ;need at least 20 machine cycles between clock pulses

delay_loop:

djnz r0, delay_loop

ret





pak_send:

;send byte from accumulator to PAK II

mov pak_byte, a

mov C, p_bit7

mov Sin, C

lcall pak_delay

setb clk

nop

nop

clr clk

lcall pak_delay



mov C, p_bit6

mov sin, c

lcall pak_delay

setb clk

nop

nop

clr clk

lcall pak_delay



mov C, p_bit5

mov Sin, C

lcall pak_delay

setb clk

nop

nop

clr clk

lcall pak_delay



mov C, p_bit4

mov sin, c

lcall pak_delay

setb clk

nop

nop

clr clk

lcall pak_delay



mov c, p_bit3

mov sin, c

lcall pak_delay

setb clk

nop

nop

clr clk

lcall pak_delay



mov C, p_bit2

mov Sin, C

lcall pak_delay

setb clk

nop

nop

clr clk

lcall pak_delay



mov C, p_bit1

mov sin, c

lcall pak_delay

setb clk

nop

nop

clr clk

lcall pak_delay



mov c, p_bit0

mov sin, c

lcall pak_delay

setb clk

nop

nop

clr clk

lcall pak_delay







ret



pak_wait:

;wait until PAK is no longer busy



jb busy, pak_wait

ret



pak_get:

;this routine gets a byte from the PAKII as input

setb Sin

lcall pak_delay

lcall pak_delay



mov c, Sout

mov p_bit7, c

setb clk

nop

nop

clr clk

lcall pak_delay



mov c, Sout

mov p_bit6, c

setb clk

nop

nop

clr clk

lcall pak_delay





mov c, Sout

mov p_bit5, c

setb clk

nop

nop

clr clk

lcall pak_delay





mov c, Sout

mov p_bit4, c

setb clk

nop

nop

clr clk

lcall pak_delay



mov c, Sout

mov p_bit3, c

setb clk

nop

nop

clr clk

lcall pak_delay





mov c, Sout

mov p_bit2, c

setb clk

nop

nop

clr clk

lcall pak_delay



mov c, Sout

mov p_bit1, c

setb clk

nop

nop

clr clk

lcall pak_delay





mov c, Sout

mov p_bit0, c

setb clk

nop

nop

clr clk

lcall pak_delay



mov a, pak_byte



ret

AWC Electronics - PAKs and 8051s