External memory accessing in XGATE ?

YongJun — Thu, 13 Apr 2006 11:51:47 GMT

Dear.

I have some problems in using XGATE to access external memories.

I designed TFT Lcd control system through MC9S12XDP512 , and external flash memory is connect to CS0 and lcd contoller to CS1.

I hope to transfer image data from external flash memory to lcd controller using

XGATE.

However , trying to access global address in XGATE Code, the system become halt.

// interrupt handler
interrupt void SoftwareTrigger0_Handler(MyDataType* __restrict pData) {

unsigned long ulAddr;

for(ulAddr=0;ulAddr<0x1000;ulAddr++) {
*(word *)(0x180000L + (ulong)(ulAddr<<1)) = 0x0000;
}

// Clear Software Trigger.
*(word *)(0x380+0x18) = 0x0100;
}

How can I access external memory in XGATE code?

Message Edited by YongJun on 04-12-200611:52 PM

Re: External memory accessing in XGATE ?

Alban — Thu, 13 Apr 2006 14:28:29 GMT

Hello,

On S12XDP family, the XGate has no access to the external addressing space.

Please have a look at the XGate memory map in the device datasheet and it will show you how the 64KB space is attributed.

Cheers,
Alban.