Problem with SPI-bus (GM862-GPS -> AtMega88)

GPS/GNSS Development Boards
1

Hello!

I’m trying to send/receive bytes from GM862-GPS to AtMega88 through SPI-bus.

I have connected GM862 to Mega88 as follows:

GM862----Mega88

GPIO3----SCLK

GPIO4----MOSI

GPIO5----MISO

GPIO6----RST

So I import, create and initialize the bus:

import SPI
SPIbus=SPI.new(3,4,5)
SPIbus.init(0,0)
SPIbus.sendbyte(0xAC)

Everything works fine until I run the “sendbyte” command. That’s when the script stops.

I don’t have SS-signal wired between GM and Mega. Does AtMega88 require SS-signal when enabling SPI-bus as slave? I cannot wire the SS-signal anymore on my proto board (well I can but it’s pretty difficult). I also tried grounding the SS-pin on Mega88. Is there any other solution than wiring the SS?

I can successfully set pin values with the GPIO build-in module etc…