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Z20X Bus

The system can be expanded by adding various modules to the expansion bus. All signals have 3.3V logic. External modules need to follow the same pinout as in the picture below.

 

GND

+5V

A0

A2

A4

A6

A8

A10

A12

A14

A16

A18

A20

A22

MEM#

RD#

INSTR#

BUSACK#

WAIT#

HALT#

D1

D3

D5

D7

CS1#

CS3#

PB2

PC0/TxD1

PD0/TxD0

PD2/RTS0#

PD4/DTR0#

PD6/DCD0#

SCL

SOUND

unused

GND

• 1     2 •

• 3     4 •

• 5     6 •

• 7     8 •

• 9    10 •

• 11   12 •

• 13   14 •

• 15   16 •

• 17   18 •

• 19   20 •

• 21   22 •

• 23   24 •

• 25   26 •

• 27   28 •

• 29   30 •

• 31   32 •

• 33   34 •

• 35   36 •

• 37   38 •

• 39   40 •

• 41   42 •

• 43   44 •

• 45   46 •

• 47   48 •

• 49   50 •

• 51   52 •

• 53   54 •

• 55   56 •

• 57   58 •

• 59   60 •

• 61   62 •

• 63   64 •

• 65   66 •

• 67   68 •

• 69   70 •

• 71   72 •

GND

+5V

A1

A3

A5

A7

A9

A11

A13

A15

A17

A19

A21

A23

IO#

WR#

FREQ_CPU

BUSREQ#

NMI#

D0

D2

D4

D6

CS0#

CS2#

PB0/T0IN

PB5/T5OUT (FLASH_CS#)

PC1/RxD1

PD1/RxD0

PD3/CTS0#

PD5/DSR0#

PD7/RI0#

SDA

RESET#

unused

GND

 

 

Physically the bus is built from a standard dual-row 72-way header with 2.54mm (0.1”) pitch.

A suggested mechanical format of Z20X controller is shown in the picture.

 

108mm

 

 

 

 

 

 

60mm

 

External connectors on this end

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Expand this side if needed

 

 

 

 

8.28mm

 

Pin 1                 Bus Connector here

 

8.28mm