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BIT 0
BIT 1
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
For example, if the display reads: 0044 A.F.
This indicates the contents of the A register is 0 and the ZERO and PARITY Flags are both set.
B.C.
This key displays the contents of the BC register pair. The BC register pair is displayed as four hex digits.
Starting from the left display, the first pair of displays represent the contents of the B register and the
second pair represent the contents of the C register. The displayed value may be changed by entering the
desired hex number using the numeric keys and then pressing the "Enter & Inc." key.
D.E.
This key displays the contents of the DE register pair. The DE register pair is displayed as four hex digits.
Starting from the left display, the first pair of displays represent the contents of the D register and the
second pair represent the contents of the E register. The displayed value may be changed by entering the
desired hex number using the numeric keys and then pressing the "Enter & Inc." key.
H.L.
This key displays the contents of the HL register pair. The HL register pair is displayed as four hex digits.
Starting from the left display, the first pair of displays represent the contents of the H register and the
second pair represents the contents of the L register. The displayed value may be changed by entering
the desired hex number using the numeric keys and then pressing the "Enter & Inc." key.
S.P.
This key displays the contents of the stack pointer. The stack pointer is a 16 bit register, displayed as four
hex digits. The displayed value may be changed by entering the desired hex number using the numeric
keys and then pressing the "Enter & Inc." key.
P.C.
This key displays the contents of the program counter. The program counter is a 16 bit register, displayed
as four hex digits. The displayed value may be changed by entering the desired hex number using the
numeric keys and then pressing the "Enter & Inc." key.
Run
This key causes the microprocessor to execute a program at full speed starting at the current program
counter (PC) address. The program will continue to execute until an optional software breakpoint is
encountered or until a RST 7 (FF hex) instruction is executed.
1
This key invokes the PRIMER diagnostics. See "Getting Started" for more details.
2
This executes the MOS service selected by the value in the C register, only affecting the registers that
pass data back from the service. No instructions need to be stored in memory and the PC register is not
affected. For more details see "Using MOS Services".
3
This enables a PRIMER with a Deluxe or Standard Upgrade Option to receive an Intel hex file through its
serial port. See the end of the lesson "Writing Your Own Programs" for more information.
4
This invokes the EPROM programmer menu driven interface. This requires the optional EPROM
PROGRAMMER BOARD, the standard or deluxe upgrade option and a connection to a dumb terminal or
terminal emulation package running on a PC. Documentation on this interface is included when you
purchase the EPROM PROGRAMMER BOARD.
CARRY FLAG
not used
PARITY FLAG
not used
AUX. CARRY FLAG
not used
ZERO FLAG
SIGN FLAG
(if this bit is 1 it indicates a carry)
(if this bit is 1 it indicates an even number of bits, odd parity)
(if this bit is 1 it indicates a carry from bit 3 to bit 4 in the A
register)
(if this bit is 1 it indicates a zero result)
(if this bit is 1 it indicates bit 7 of the A register is a 1)
84
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