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Warning
: if you want to use the K7 connector when Mainboard is
connected to the CPU board, you have to disconnect the selected
serial interface (UART0 or UART1) from the RS232 drivers on the
Mainboard. To achieve this, remove jumpers on positions 3-4, 5-6
from both the J21 and J22 headers on the Mainboard. Also, when the
Mainboard is connected to the CPU board and the Async. Serial
programming mode is set on the Mainboard
System control DIP switches
,
the FPGA UART is connected to UART0 or UART1 (depending on
the setting of the UART0/1 switch) after reset. If you want to use K7
also in that case, remove the 3-4, 5-6 jumpers on the J23.
Default setting: the UART1 signals are connected to the K7.
J19, J20: I
2
C software emulation jumpers
These jumpers allow to use Mainboard’s I
2
C connector/EEPROM memory even
in the case, when CPU itself doesn’t provide the I
2
C interface. When both of
these jumpers are SHORT, the CPU’s HRQ signal is connected to the
Mainboard’s SDA signal (via J19) and #HAK signal is connected to SCL signal.
An user can then program the #HAK, HRQ signals to behave as I
2
C interface.
J15, J16: Low speed XTAL jumpers
When short, these jumpers connect the 32.768 kHz crystal to the Bus Interface
connector X1A, X0A pins.
J17, J18: High speed XTAL jumpers
When short, these jumpers connect the 4MHz crystal to the Bus Interface
connector X0, X1 pins.
SW1 – Reset button
This button can be used for reseting the CPU.
SW2 – Hardware standby button
While this button is pressed, the CPU stays in the standby mode (all oscillators
are stopped, all I/O pins are set to high impedance state, special purpose registers
such as the accumulator are reset to their default values, but content of internal
RAM is preserved)
SW3 – CPU DIP switches
1: MD0
2: MD1
3: MD2
4: S-R
5: S-H
6: H-R
7: AD00 (P00)
8: AD01 (P01)
8 7 6 5 4 3 2 1
ON
