MCP23S17 init all outputs and to a logic 1

Hello to All-
I have been trying to figure out the best and/or fastest way to initialize a MCP23S17 (SPI) to all outputs with an active low.
I init the devices by calling this routing (Thanks to the Forum)

Code:

INIT_OutA_2317:'MCP2317 used for A Outputs: OutA_MCPReg = IOCON 'Configures the MCP23S17 OutA_DataOut = $20 GOSUB SEND_OutA_2317 OutA_MCPReg = IODIRA 'Configures PortA(1) All OUTPUTS OutA_DataOut = $00 GOSUB SEND_OutA_2317 OutA_MCPReg = IODIRB 'Configures PortB(2) All OUTPUTs OutA_DataOut = $00 GOSUB SEND_OutA_2317 RETURN

And the Send Out Sub:

Code:

SEND_OutA_2317: CSA = 0 'Enable the MCP23S17 SSP1BUF = MCPWRT 'Command to Write to the MCP23S17 while !PIR1.3 : wend PIR1.3=0 'Reset the flag SSP1CON1.7=0 'Clear collision bit SSP1BUF = OutA_MCPReg 'Register to Write the Data while !PIR1.3 : wend PIR1.3=0 'Reset the flag SSP1CON1.7=0 'Clear collision bit SSP1BUF = OutA_DataOut 'Data to be sent while !PIR1.3 : wend PIR1.3 = 0 'Reset the flag SSP1CON1.7=0 'Clear collision bit CSA = 1 'Disable the MCP23S17 RETURN

And the set port sub:

Code:

SetPort_A: OutA_hi=OutA.highbyte 'Splits into hibyte OutA_lo=OutA.lowbyte 'And into low byte of the word var OutA_MCPReg = OLATA 'Sets up PORTA output OutA_DataOut=OutA_lo 'Sets up data to be pushed to the MCP23S17 as the low byte gosub SEND_OutA_2317 'Send it pause 3 'Wait a bit OutA_MCPReg = OLATB 'Sets up PORTB output OutA_DataOut=OutA_hi 'Sets up data to be pushed to the MCP23S17 as the hi byte gosub SEND_OutA_2317 'Send it return

And then do a for next loop:

Code:

for i=0 to 15 : OutA.0[i]=1 : gosub SetPort_A : next i

Even working with a 18F6527 at 40 MHz, the thing comes up with all outputs active (active low is what I am looking to do) for a small time but fast enough to trigger all 16 outputs.
I will try cutting some of the pauses but is there a better/faster way to do this?
Any pointers would be helpful - as is always this forum......

Re: MCP23S17 init all outputs and to a logic 1

from data sheet

Quote:

Serial Data to Output Valid— — 450 ns

Quote:

CS Setup Time 50 nS

a 3mS pause is way to long

Quote:

SetPort_A:
OutA_hi=OutA.highbyte 'Splits into hibyte
OutA_lo=OutA.lowbyte 'And into low byte of the word var
OutA_MCPReg = OLATA 'Sets up PORTA output
OutA_DataOut=OutA_lo 'Sets up data to be pushed to the MCP23S17 as the low byte
gosub SEND_OutA_2317 'Send it
pause 3 'Wait a bit cannot see that this is necessary or even adds any value
OutA_MCPReg = OLATB 'Sets up PORTB output
OutA_DataOut=OutA_hi 'Sets up data to be pushed to the MCP23S17 as the hi byte
gosub SEND_OutA_2317 'Send it
return

if you want speed why set only 1 bit at a time when they all are going to be set anyway

Quote:

for i=0 to 15 : OutA.0[i]=1 : gosub SetPort_A : next i

Code:

OutA=$ffff gosub SetPort_A

would be 15 times faster

Re: MCP23S17 init all outputs and to a logic 1

Thanks Richard!
I get caught up thinking in terms of 8 bits that I forget that I can actually speak in words! Hah!
I did miss the PAUSE statement and have changed it to PAUSEUS 10 and it seems happy.
I used the OutA=$FFFF : gosub SetPort_A and it seems that it too fast for the outputs to actually toggle which is what I was driving for.
Thanks again, good eye and quite helpful.
Steve