It sounds like you are already doing this correctly, but below is the function that I use to enable the PC104 bus on the 7800 to access expansion boards.
It is part of a larger class but I think clearly demonstrates how to convert the PC104 bus to ISA.
Maybe it will be helpful.
#define ARM9_REGISTER 0xE8000000 //ARM9 registers
int TS7800_ExpansionBoard::setPC104toISA()
{
volatile unsigned int *regs;
//Check to make sure we have a FD for memory device
if ( _intDevMem < 1 )
{
openMemoryMapDevice(O_RDWR|O_SYNC);
}
//Get pointer to base address
regs = (unsigned int *)mmap(0, getpagesize(), PROT_READ|PROT_WRITE,
MAP_SHARED, _intDevMem, ARM9_REGISTER);
if ( regs == MAP_FAILED )
{
// TODO: Log the error
perror("Error occurred while getting memory map file.\n");
exit(1);
}
//Set the PC104 bus to ISA so we can talk to peripheral devices
*(regs + 0x30/sizeof(unsigned int)) = 0x55555555;
*(regs + 0x34/sizeof(unsigned int)) = 0x55555555;
*(regs + 0x38/sizeof(unsigned int)) = 0x55555;
*(regs + 0x3C/sizeof(unsigned int)) = 0x55555;
//Unmap the memory map since we are done with it
munmap((void *)regs, getpagesize());
regs = NULL;
return 0;
}
On Thu, Jan 29, 2009 at 5:21 AM, Christian Gagneraud <> wrote:
charliem_1216 wrote:
> Hi Chris --
>
> --- In ts-7000%40yahoogroups.com, Christian Gagneraud <>
> wrote:
>> Hi there,
>>
>> According to the ts7800 manual, there's a register at address
>> 0xE800000C to control the timing of the PC/104 bus, and this register
>> should contains some default power-on values.
>
> IIRC, the ts7800 comes up in GPIO mode, and you have to switch to
> ISA/PC-104 mode by writing to some registers. Are you doing that already?
Yes, I do. Thre's 4 registers for this purpose. But then there is this
one to fine-tuned the bus timing...
>
> regards, ........ Charlie
>
>> My problem is that if i read the register with a "peek32 0xE800000C",
>> i get 0x16bdc, which doesn't correspond to the expected value. For a
>> default ISA strobe length of 40 and a default setup length of 14, i
>> should get something like 0x162A8.
>>
>> If i try with 0x162FF (max timing), the system freeze as soon as i try
>> to read anything. 0x162A8 seems to work better, i can see that the
>> peripheral board is accessed (there's a LED that show PC104 access on
>> it), but the values returned looks a bit random.
>>
>> I would like to configure the ISA bus in a state which will be as
>> compatible as possible with the ISA specs.
>> Can anyone explain me why do i get these default power-on values? And
>> which value will really put me into a kind of ISA compliant mode?
>>
>> I tried to play with this register, since i can't get a peripheral
>> board working, the kernel module need to read/write a couple of
>> registers on the bus, unfortunately reading these registers return
>> always 0, and i'm sure that i should get something different.
>> Basically, here is what the code is doing:
>>
>> // board configured for ISA address 0x180
>> int io_base = 0xEE000000 + 0x180
>> volatile uint8_t* reg_base = __ioremap( io_base, 4096, 0);
>> uint8_t value = *reg_base;
>> // value is always 0x00 with peek32 0xE800000C 0x16bdc
>> // value looks a bit random with peek32 0xE800000C 0x162A8
>>
>> With best regards,
>> Chris
>>
>
>
>
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