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Z8018x
Family MPU User Manual
11
TOUT. Timer Out (Output, Active High). TOUT is the pulse output from
PRT channel 1. This line is multiplexed with A18 of the address bus.
TXA0, TXA1. Transmit Data 0 and 1 (Outputs, Active High). These
signals are the transmitted data from the ASCI channels. Transmitted data
changes are with respect to the falling edge of the transmit clock.
TXS. Clocked Serial Transmit Data (Output, Active High). This line is
the transmitted data from the CSIO channel.
WAIT. Wait (Input; Active Low). WAIT indicates to the CPU that the
addressed memory or I/O devices are not ready for a data transfer. This
input is used to induce additional clock cycles into the current machine
cycle. The WAIT input is sampled on the falling edge of T2 (and
subsequent Wait States). If the input is sampled Low, then additional Wait
States are inserted until the WAIT input is sampled High, at which time
execution continues.
WR. Write (Output, Active Low, 3-state). WR indicates that the CPU data
bus holds valid data to be stored at the addressed I/O or memory location.
XTAL. Crystal (Input, Active High). Crystal oscillator connection. This
pin must be left open if an external clock is used instead of a crystal. The
oscillator input is not a TTL level (reference DC characteristics).
Multiplexed pins are described in Table 2.
UM005004-0918
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Questions and answers
are there a timing diagrams for PUSH and POP instructions?
The timing diagrams for the PUSH and POP instructions for the ZiLOG Z8018 Series are as follows:
POP Instruction (e.g., POP IX or POP IY):
- Machine Cycle 1 (MC1): Fetch POP opcode.
- Machine Cycle 2 (MC2): Fetch address code.
- Machine Cycle 3 (MC3): Read from memory at SP (Stack Pointer); data goes to low byte (e.g., IXL or IYL).
- Machine Cycle 4 (MC4): Read from memory at SP+1; data goes to high byte (e.g., IXH or IYH).
PUSH Instruction (e.g., PUSH IX or PUSH IY):
- Machine Cycle 1 (MC1): Fetch PUSH opcode.
- Machine Cycle 2 (MC2): Fetch address code.
- Machine Cycle 3 (MC3): Decrement SP by 1 and write high byte (e.g., IXH or IYH) to memory at SP.
- Machine Cycle 4 (MC4): Decrement SP by 1 and write low byte (e.g., IXL or IYL) to memory at SP.
Each machine cycle includes three T-states (T1, T2, T3), and memory control signals (such as MREQ, RD, WR) are active as needed during these cycles.
This answer is automatically generated