Connector recommendations
The IDC connector supplied with the GEMINI-1 programmer is ‘bump’ polarised so that it
can not be inserted the wrong way around in a polarised socket. If the connector used on
the target system is not polarised, it is advised that measures are taken to prevent the
connector being plugged in the wrong way around. This could be achieved by removing pin
8 (a second ground) from the target header and placing a
blanking piece of plastic in pin 8 of the cable header.
User Guide V0.90
19
ISP Pin Assignments
Pin GEMINI-1
Target Microcontroller Description
Pin Name
Pin Name
1
PROG_Vcc
Vcc
Target Vcc connection
2
PROG_Vpp
EA/Vpp
Target Vpp pin - Vpp is applied to this pin (if required)
3
PROG_PSEN
PSEN
Driven LOW by programmer to enter ‘Boot Loader’ mode
4
PROG_TXD
RXD
Programmer Transmit line
5
PROG_ACTIVE
LED or Interrupt pin
Programmer Active LED/Interrupt pin
6
PROG_RXD
TXD
Programmer Receive line
7
PROG_GND
Vss
Target GROUND (Vss) connection
8
N/C
-
-
9
PROG_GND
Vss
Target GROUND (Vss) connection
10
PROG_RESET
RESET
Target RESET control pin
Y
= This connection must be made
x
= Optional
N/C
= No Connect
MCU
= ??????????????????
ISP Header (Target System)
GEMINI-1 - Target System Connection
Details
The programmer 10-way ribbon cable supplied is
terminated with a standard 10-way 0.1" pitch IDC plug.
This is designed to mate with the complimentary male
10-way IDC header on the target system. The pin-out of
the header is shown opposite:
2
3
5
7
8
6
4
9
1
10
N/C
PROG_TXD
PROG_RESET
PROG_RXD
PROG_PSEN
PROG_ACTIVE
PROG_Vcc
PROG_GND
PROG_GND
PROG_VPP
10-Way IDC Header
Top Pin View
Note:
This is the view of the connector fitted to the target
board, as seen from above (the component side).
