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Chapter 1 Architectural Overview
The Am29245 is intended for use in systems which do not need the maximum
performance of the Am29240 or all of its peripherals; and can benefit from a reduced
processor cost. The Am29245 does not support Scalable Clocking and is only avail-
able at relatively lower clock speeds.
1.9.3 The Am2924x Evaluation
AMD has a number of boards available for Am2924x evaluation. Microcontrol-
lers in this family grouping all have the same pin configuration. This enables the
boards to operate with any of the Am2924x processors. The least expensive board is
the SD29240 it is a very small board, similar in form to the SA29200 board; it does
not have the expansion connector available with the SA29200. It is normally sup-
plied with an Am29240 or Am29245 installed. There is 1M byte of 32–bit wide
DRAM which operates at 16 MHz. When an Am29240 is used, Scalable Clocking
can enable the processor to operate at 32 MHz. The board also has a JTAG and
RS–232 connector. The 1M byte of 32–bit wide EPROM supplied with the board is
preprogrammed for MiniMON29K operation.
Those with more money to spend, or requiring a more flexible evaluation board,
can use the SE29240 board. It contains an Am29243 processor but can be used to
evaluate an Am29240 or Am29245. Initially the board contains 1M byte of 36–bit
wide DRAM. However, this can be expanded considerably. The DRAM is 36–bits
wide due to the additional 4–bits required for parity checking. The maximum
memory speed is 25 MHz. Scalable Clocking can be used with a 32 MHz processor
when the memory system is configured for 16 MHz operation.
The SE29240 board has greater I/O capability than the SD29240 board. There
are connectors for two RS–232 ports and a parallel port. Debugging can be achieved
via a serial or parallel port link to the MiniMON29K DebugCore located in EPROM.
Debugging is also supported via the JTAG or Logic Analyzer connections. There is a
small wire–wrap area for additional circuitry, and extra boards can be connected via
an expansion connector.
AMD also has an evaluation board intended for certain communication applica-
tions. The NET29K board has a triple processor pad–site. The board can operate with
either an Am29205, Am29200 or Am2924x (probably an Am29243) processor. The
processor pad site is concentric, the larger processor being at the outer position. The
similarity in the memory region controllers enables the construction of this unusual
board.
The memory system consists of 4M bytes of 36–bit wide DRAM, which is ex-
pandable. There is also 2M bytes of 32–bit EPROM. The EPROM can be replaced
with 1M byte of Flash programmable memory. For communications there is an AMD
MACE chip which provides an Ethernet capability via an 10–Base–T connector. Two
of the processors DMA channels are wired for MACE access. Once channel of an
85C30 UART is connected to an RS–449 connector which supports RS–422 signal