S12 / MagniV MicrocontrollersのトピックRe: 9S12XDP512: Question about the three SPI's

9S12XDP512: Question about the three SPI's

DavidN_ — Mon, 16 Mar 2009 04:16:18 GMT

I have read the datasheet for the MC9S12XDP512 on the SPI section. There is only one memory map for the SPI. Does this mean that if I set the SPE in the in the SPICR1 register, it will turn on all three SPI's of the MCU? Also, does this mean that they will use the same SPIDR register?

If this is the case, then there is no sense in making three SPI ports when I could just connect multiple devices to one SPI port and select each one utilizing the slave select signal.

I have tried to look for application notes on this but could not find any. What I want to know is, are there separate memory maps for each SPI in this MCU so that each SPI could have its own clock rate and its own data line?

I appreciate any help. Thanks.

Re: 9S12XDP512: Question about the three SPI's

kef — Mon, 16 Mar 2009 12:01:37 GMT

What datasheet are you using? MC9S12XDP512 Data Sheet Rev 2.17 Table 1-1. Device Register Memory Map: 0x00D8-0x00DF - SPI0, 0x00F0-00F7 - SPI1, 0x00F8-0x00FF - SPI2

Re: 9S12XDP512: Question about the three SPI's

bigmac — Mon, 16 Mar 2009 12:24:38 GMT

Hello,

The three sets of registers should also be defined within the header file for the MC9S12XDP512.

Regards,

Mac

Re: 9S12XDP512: Question about the three SPI's

DavidN_ — Mon, 16 Mar 2009 12:26:31 GMT

Ah sorry. It was in Appendix G on page 1322. Never thought to look that far.. My mistake. Sorry to bother.