The test board for F21d- could be quite similar to the PCB for F21b. The board could have chips on both sides, or surface mount, or a SIMM, and F21 or MuP21h. It coule have DRAM, SRAM or a combination, ROM or FLASH and could support jumpering for both. I have laid out one wire wrap test board but haven't finished wiring it. The board could have no voltage regulator while testing on a lab bench, but should have space for a clock oscillator (or xtal), and power regulator and connectors for the analog and digital I/O to be tested.

I think we are past the test point stage. So it should be designed as a small and simple board that will accept F21d, or some F21d and some I21 prototypes, or F21d and Offete Enterprise Inc.'s MuP21h 44 pin PLCC.

Chuck has done a wire wrap test board for i21
with 1Mx4 DRAM zipps and has suggested a wire wrap layout for F21
similar to

  front side viewed from front
   +----------------------+
   | PPort.......  +----+ |
   | Ni +--F21c-+  | p f| |
   | No | +---+ |  | r l| |
   | RGB| |P21| |  | o a| |
   | Ai | +---+ |  | m s| |
   | Ao +-------+  | / h| |
   |               +----+ |
   | Reset [osc] [Reg]    |
   | =====DRAM SIMM ===== |
   +----------------------+


            bottom
  back side viewed from front
   +----------------------+
   |                      |
   |                      |
   |                      |
   |                      |
   |                      |
   |                      |
   | ==================== |
   +----------------------+



These are some of my suggested layouts, but I haven't tried to
route them on a two layer board, or four layer board.

              top
  front side viewed from front
   +------------------------+
   |PPort....... +--+ +----+|
   |Ni +--F21c-+ |s | | p f||
   |No | +---+ | |r | | r l||
   |RGB| |P21| | |a | | o a||
   |Ai | +---+ | |m | | m s||
   |Ao +-------+ +--+ | / h||
   |Reset [osc] [Reg] +----+|
   +------------------------+

            bottom
  back side viewed from front
   +------------------------+
   |              +--+ +--+ |
   | d  d  d  d  d|s | |s | |
   | r  r  r  r  r|r | |r | |
   | a  a  a  a  a|a | |a | |
   | m  m  m  m  m|m | |m | |
   |              +--+ +--+ |
   |                        |
   +------------------------+

Or with 2 dram (2x16x1M or 16x1M + 4x1M)

  front side viewed from front
   +------------------------+
   |PPort....... +--+ +----+|
   |Ni +--F21c-+ |s | | p f||
   |No | +---+ | |r | | r l||
   |RGB| |P21| | |a | | o a||
   |Ai | +---+ | |m | | m s||
   |Ao +-------+ +--+ | / h||
   |Reset [osc] [Reg] +----+|
   +------------------------+

            bottom
  back side viewed from front
   +------------------------+
   |              +--+ +--+ |
   |    d     d   |s | |s | |
   |    r     r   |r | |r | |
   |    a     a   |a | |a | |
   |    m     m   |m | |m | |
   |              +--+ +--+ |
   |                        |
   +------------------------+

Or w/o SRAM

  front side viewed from front
   +-------------------+
   |PPort....... +----+|
   |Ni +--F21c-+ | p f||
   |No | +---+ | | r l||
   |RGB| |P21| | | o a||
   |Ai | +---+ | | m s||
   |Ao +-------+ | / h||
   |             +----+|
   |Reset [osc] [Reg]  |
   +-------------------+

            bottom
  back side viewed from front
   +-------------------+
   |                   |
   |    d     d        |
   |    r     r        |
   |    a     a        |
   |    m     m        |
   |                   |
   |                   |
   +-------------------+

Or with hole through socket for F21 so nothing can
be mounted behind it.

  front side viewed from front
   +------------------------+
   |PPort....... +--+ +----+|
   |Ni +--F21c-+ |d | | p f||
   |No | +---+ | |r | | r l||
   |RGB| |P21| | |a | | o a||
   |Ai | +---+ | |m | | m s||
   |Ao +-------+ +--+ | / h||
   |Reset [osc] [Reg] +----+|
   +------------------------+

            bottom
  back side viewed from front
   +------------------------+
   |               +--+     |
   |               |d |     |
   |               |r |     |
   |               |a |     |
   |               |m |     |
   |               +--+     |
   |                        |
   +------------------------+


or a hole through socket for F21 can
be used with a board with no dram.

              top
  front side viewed from front
   +------------------------+
   |PPort....... +--+ +----+|
   |Ni +--F21c-+ |s | | p f||
   |No | +---+ | |r | | r l||
   |RGB| |P21| | |a | | o a||
   |Ai | +---+ | |m | | m s||
   |Ao +-------+ +--+ | / h||
   |Reset [osc] [Reg] +----+|
   +------------------------+

            bottom
  back side viewed from front
   +------------------------+
   |              +--+ +--+ |
   |              |s | |s | |
   |              |r | |r | |
   |              |a | |a | |
   |              |m | |m | |
   |              +--+ +--+ |
   |                        |
   +------------------------+
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