Introduction
This document gives some details about the hardware configuration of the Smaky 400
board. The three main components of the board are :
- The main CPU (usually, a QFP MC68LC040 running at 33 MHz).
- The MC68360 (also called QUICC by Motorola).
- The QSpan PCI to host bridge. The bus on the main CPU side is called Q-bus
by Tundra.
You definitely need the MC68360 User's Manual and the QSpan User's Manual (both are
available in PDF format on the web or as printed material at Motorola and Tundra's) in
order to properly initialise and set up the Smaky 400 board.
Resource map
The Smaky 400 board does not have a fixed resource address map. The address of each
peripheral can be defined thanks to the 68360 SIM, which is responsible for address
decoding. It generates the /CSx signals which
are routed as following :
| /CS0 |
Boot chip select, not used, available on
expansion connector. |
| /CS1 |
Free chip select, not used, available on
expansion connector. |
| /RAS2 |
Row Address Strobe for DRAM bank 0. |
| /RAS3 |
Row Address Strobe for DRAM bank 1. |
| /CS4 |
Free chip select, not used, available on
expansion connector. |
| /CS5 |
Mubus chip select. |
| /CS6 |
QSpan internal register chip select. |
| /CS7 |
QSpan PCI image chip select (image
selected through A31). |
Boot procedure
The Smaky 400 board design does not include ROMs nor any other kind of non-volatile
storage on which the main CPU could boot. Therefore, it is the hosts responsibility
to set up the memory before starting the main CPU.
This set up procedure can be described as following :
- Configure the QSpan so that the host processor can access the Q-bus, then
pulse the software reset signal (register misc_ctl).
- Set up the MBAR in the 68360 (access address
is 0x0003FF00 in CPU space mode 7) with the
proper mask and enable bits.
- Set up the SYPCR in the 68360 (System
Protection Control Register, 6.9.3.5) in order to disable the software watchdog;
otherwise, the 68360 would be reset again in less than a second.
- Initialise the 68360 (memory decoding, pin assignment registers, etc.) as needed. The PEPAR has to be initialised as following :
- /IOUT2..0 map to pins 203, 202 and 199.
- /BCLRO is an output on pin 210.
- /BCLRI is an input on pin 207.
- A31..28 map to address lines, not /WE0..3.
- AMUX is output on pin 212.
- /CAS3..2 and /CAS1..0
are output on pins 182, 183, 185 and 187.
- /CS7 is output on pin 171.
- /AVECO is output on pin 233.
- Test the DRAM and set up the refresh accordingly. Memory is seen contiguously within a
given bank.
- Download the boot code for the main CPU to the DRAM and make sure it has been mapped to
address 0x00000000.
- Start the main CPU by actively driving high the PB16
output (directly connected to the /RSTI pin of
the main CPU; a 1 K pull-down insures that when the 68360 is reset, /RSTI becomes active).