User manual

Page 8
Document No. 80-15151 Issue 6 HEBER LTD
5.4.3 DMA Controller Module
The DMA Module provides 2 DMA Channels. On the Pluto 5 these are used for sending sound data
from the Programme Memory to the OKI MSM6585 Sound Chip(s). DMA Channel 1 is used to send
data to Sound Channel #1, which is fitted as standard to the Pluto 5 Board. DMA Channel 2 is used for
the optional add-on Sound Channel #2 if fitted (IC39).
The DMA channel should be set to work in following modes:
• External request
• Dual address
• Source address incrementing (Memory)
• Destination address not incrementing (FPGA sound register)
• Transfer size = byte
• Interrupt on completion
Pins controlled by the DMA module are allocated as follows:
Table 2. Allocation of MC68340 Pins Controlled by DMA Module
PIN NO. I/O FUNCTION
DREQ1- 16 I SFX Channel 1 DMA request
DACK1- 15 O No connection
DONE1- 14 IO Not used, 3K3 pull-up
DREQ2- 13 I SFX Channel 2 DMA request
DACK2- 12 O No connection
DONE2- 11 IO Not used, 3K3 pull-up
5.4.4 Serial Module
The Serial Module provides Asynchronous Comms on 2 Channels, Channel A and Channel B. It is
functionally very similar to the 1681/68681 range of DUARTs.
Channel A is buffered to RS232 levels and connected to connector P1. Signals RX, TX, RTS and CTS
are provided.
Channel B is buffered to RS232 levels and connected to DATAPORT connector P2. Signals RX, TX,
RTS and CTS are provided.
The 4 Channel A signals are also made available on the TTL Expansion Connector, P14, at TTL
levels. Thus, alternative interfaces may be provided on an Add-on Board to allow, say, RS485 or Mars
HII interfaces to be implemented.
The exact set up of the Serial Module will obviously depend upon the functionality required.