Hello,
I have built a device based on Renesas' H8/3068F and RTL8019AS. I have connected the chips in the following way: H8/3068F RTL8019AS Notes
-------- --------- ----- A[0-9] A[0-9] other Realtek's address lines tied to GND D[8-15] SD[0-7] D8SD0, D9SD1, etc. D[0-7] SD[8-15] /CS4 AEN /HWR, /LWR IOWB connected through HC08 (AND) gate /RD IORB /WAIT IOCHRDY line pulled up through 10k /IRQ0 INT0 SLOT16 pulled down though 27k In this HW configuration 8019AS has been working in 8 bit mode very well for a few months.
Last week I wanted to test Realtek's 16 bit mode (i.e. word-wide DMA transfers). The only change I made in the hardware was removing
27k resistor and pulling up SLOT16 pin through 360 ohm - just like in a 16bit slot of a PC's motherboard. Then I switched MCU data bus into 16bit mode (by apropriate ABWCR register setting) and started playing with Realtek's registers, especially with the bit WTS of the DCR. Unfortunately, without success. When I read even address, upper byte was expected register value and lower byte was 0xff. But when I read even address, I always got 0xffff. The interesting thing is that 8019 still works well in 8bit mode when SLOT16 is pulled up.Does anyone know how to force 8019AS to work in 16bit mode? I am looking for any hints, source code, schematics, etc. Any help will be appreciated.
Regards, /J.D.