MC9S12A256 I/O ports configuration

Started by chen_xuesong October 27, 2003
Hello friends,

When I am using the 16bit MCU MC9S12A256, I found Port P and Port H
can both be configured for SPI 1 and SPI 2. So if I enable SPI 1 and
SPI 2 functions, which port is working as SPI signals? I think it
should be one port for SPI and the other port for general I/O. I read
through the the manual, it mentions that both ports take precedence
as SPI than general I/O if SPI is enalbled. As such arrangement, is
it meaning that both ports are working as same SPI signals? I am
quite confused with it as new to this MCU. Thanks for your help.




Hello Chen,

The MODRR register at address x257H allows you to specify which pins the
SPI0, SP!1, SPI2, CAN0 and CAN4 should be routed to.

Hope this helps,
Doron
Nohau Corporation
HC12 In-Circuit Emulators
www.nohau.com/emul12pc.html

At 03:31 28/10/2003 +0000, you wrote:
>Hello friends,
>
>When I am using the 16bit MCU MC9S12A256, I found Port P and Port H
>can both be configured for SPI 1 and SPI 2. So if I enable SPI 1 and
>SPI 2 functions, which port is working as SPI signals? I think it
>should be one port for SPI and the other port for general I/O. I read
>through the the manual, it mentions that both ports take precedence
>as SPI than general I/O if SPI is enalbled. As such arrangement, is
>it meaning that both ports are working as same SPI signals? I am
>quite confused with it as new to this MCU. Thanks for your help.