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CSK PSPM D Bus Connections

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CSK PSPM D Bus Connections

Postby jepost » Sat Mar 01, 2014 1:30 pm

Reference CSK PSPM D
Document 00587B-2.SCH Rev. B
Sheet 2 of 5

CSK Motherboard
Document 00433E-6.SCH Rev. E
Sheet 6 of 7

1. On the PSPM D schematic bus connections for IO.0 - IO.47 are shown except for IO.3, which is labeled "SCKOA."
On the CSK Motherboard schematic IO.3 is shown, but no SCKOA. Is SCKOA also IO.3? If not, what is SKOA?

(Okay, I think I see the answer to my own question. At the top of the sheet JP1 connects either SCKOA or SCKOB to IO.3. Looks like the default is SCKOA. Bus what do "SCKOA" and "SCKOB" stand for? They aren't listed on the PIC24F pinout descriptions Table 1-4.)

2. It looks like PSPM D pin RG2 is available as SCL_SYS and RG3 is available as SDA_SYS on the CSK Bus Connector. Are any other PSPM D pins available on the CSK Bus Connector besides those available on IO.0 - IO.47?

Thanks,

ERAU EagleSat
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Re: CSK PSPM D Bus Connections

Postby Andrew » Mon Mar 03, 2014 10:34 am

jepost wrote: On the PSPM D schematic bus connections for IO.0 - IO.47 are shown except for IO.3, which is labeled "SCKOA."
On the CSK Motherboard schematic IO.3 is shown, but no SCKOA. Is SCKOA also IO.3? If not, what is SKOA?

(Okay, I think I see the answer to my own question. At the top of the sheet JP1 connects either SCKOA or SCKOB to IO.3. Looks like the default is SCKOA. Bus what do "SCKOA" and "SCKOB" stand for? They aren't listed on the PIC24F pinout descriptions Table 1-4.)

It's a lot easier to figure out if you make the connection that:
  • The choice of SCKOA or SCKOB is done via JP1
  • JP1 is labeled as "PIC24" or "dsPIC33" on the silkscreen of the PSPM D (PCB: 705-00587B)
  • The PIC24FJ256GA110 and the dsPIC33FJ256GP710 use different pins for SPI #0 clock (aka SCK0) ...
All of the above ensure that whether you have a PIC24FJ256GA110 (PPM D1) or a dsPIC33FJ256GP710 (PPM D2), the first SPI peripheral maps successfully to the SD Card on the CSK MB. This is made more complex by the fact that the dsPIC33FJ256GP710 does not have PPS, but the PIC24FJ256GA110 does ...
jepost wrote: 2. It looks like PSPM D pin RG2 is available as SCL_SYS and RG3 is available as SDA_SYS on the CSK Bus Connector. Are any other PSPM D pins available on the CSK Bus Connector besides those available on IO.0 - IO.47?

As a CSK customer, you have access to both the schematics and the datasheet for PSPM D ... they fully reveal all information re pin mappings between the processor and the CSK bus.

Note that there is a second I2C bus on IO.20 and IO.21, and a second SPI bus on IO.8 through IO.11.
Andrew
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