GPBA02A

© Generalplus Technology Inc.

Proprietary & Confidential

17

JAN. 06, 2011

Version: 1.6

Register Speed up OR function:

The content of ATTA/B/C, BUFA/B/C and DIRA/B/C can be speed

up OR with any data by executing a special write instruction.

According to the command data frame, when user writes data into

register address of 2xH (B5-4 of command is 10), the writing data

will be OR with the current data of this register and then be load in

the exact register again. While executing OR instruction, the I/O

extender reads the primary value of the register. This speed up

OR operation only spends the host a write command cycle. It is

a very useful function for I/Os’ real time control.

Register Speed up XOR function:

The content of ATTA/B/C, BUFA/B/C and DIRA/B/C can be speed

up XOR with any data by executing a special write instruction.

According to the command data frame, when user writes data into

register address of 3xH (B5-4 of command is 11), the writing data

will be XOR with the current data of this register and then be load

in the exact register again. While executing XOR instruction, the

I/O extender reads the primary value of the register. This speed

up XOR operation only spends the host a write command cycle.

It is a very useful function for I/Os’ real time control.

Comparing traditional AND/OR/XOR operation with speed up AND/OR/XOR operation

(Reference by 6502 assembler):

Traditional

Speed Up

AND Operation

Read a byte from I/O extender

MCU internal “AND”

Write a byte to I/O extender

(Example:

LDX #$01

JSR READ_SPI

AND #$55

JSR

WRITE_SPI

)

Write a byte to “AND” address

(Example:

LDA

#$55

LDX

#$11

JSR

WRITE_SPI

)

OR Operation

Read a byte from I/O extender

MCU internal “OR”

Write a byte to I/O extender

(Example:

LDX #$01

JSR READ_SPI

OR #$55

JSR

WRITE_SPI

)

Write a byte to “OR” address

(Example:

LDA

#$55

LDX

#$21

JSR

WRITE_SPI

)

XOR Operation

Read a byte from I/O extender

MCU internal “XOR”

Write a byte to I/O extender

(Example:

LDX #$01

JSR READ_SPI

XOR #$55

JSR

WRITE_SPI

)

Write a byte to “XOR” address

(Example:

LDA

#$55

LDX

#$31

JSR

WRITE_SPI

)

Note:

The sub routine READ_SPI and WRITE_SPI depends on the host structure, it takes at least 34 IO access cycles (enable*2+data_clock*8*2*2, no include

data and flow control process) while using software to generate SPI waveform.