ECP和EPP接口的概念

[xiao_feng]

小弟最近做一个并口的设备，找了一堆IEEE 1284的资料，可是俺对ECP和EPP接口的概念还不是很明确。俺的理解如下，不知道对不对：
void epp_addr_write(nBaseAddress, nValue)
{
outp (nBaseAddress + 3, nValue);
}

void epp_data_write(nBaseAddress, nValue)
{
outp (nBaseAddress + 4, nValue);
}

int epp_data_read(nBaseAddress)
{
return inp (nBaseAddress + 4);
}

void ecp_addr_write(nBaseAddress, nValue)
{
outp (nBaseAddress, nValue);
}

void ecp_data_write(nBaseAddress, nValue)
{
outp (nBaseAddress + 0x400, nValue);
}

int ecp_data_read(nBaseAddress)
{
return inp (nBaseAddress + 0x400);
}