Getting Started
SOCKET ASSIGNMENTS
Memory chip socket Row A includes sockets 4A, 5A, 6A, and 7A.
Memory chip socket Row B includes sockets 4B, 5B, 6B, and 7B.
Socket 4A/B is always in the lowest address range of the row when
using Ziatech initialization software, and socket 7A/B is always the
highest.
28-pin memory chips must be inserted with socket pins 1, 2, 31 and
32 empty. When looking at the ZT 8825 circuit board with the
component side facing you and the edge connector at the bottom, 28-
pin chips should be installed in the bottom-most section of the socket.
WRITE PROTECT
When debugging programs in RAM, there is a tendency for certain
programming errors to cause undesired writes to RAM. The ZT 8825
has a write-protect switch (SW2) that can be used to prevent writes to
any of the memory chips installed on the board. This switch is located
near the outside edge of the board for easy access. The switch is
positioned up away from the board for write enable, down toward the
board for write protect.
The RAM may also be software write-protected by setting bit 3 of the
Configuration Register to logic 0. Bit 3 is logic 0 at power-on or reset
time. Both SW2 and bit 3 must be enabled to allow writing to the
RAM. If either is in protect mode, the RAM will be protected.
2-5
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