OPERATING PRINCIPLES
2.3.2 Reset Circuit
This section describes the hardware reset circuit. When the hardware reset signal is input, all ICs in the control circuit are reset, and the CPU executes the program from the starting address. Figure
The circuit is equipped with a reset IC: PTS591(IC13) is used for resetting the + 5 VDC line. The reset operation is described below.
‰Power On/Off Reset:
Reset IC PTS591 (IC13) monitors the +5 VDC line on the C204 MAIN board. If it drops to 4.2 VDC or smaller, the reset IC outputs a LOW signal to the CPU (IC2) and E05B36 (IC1) gate array.
‰Forced Reset:
The gate array outputs the RSTOUTX or ERRCRPFX signals to the XRESET of the CPU, and also to the gate array itself.
‰/INIT Signal Reset:
When the gate array receives the /INIT signal from the host computer, the signal is transferred to the INT4 of the CPU, then CPU performs the /INIT reset operation.
+5
| R215 |
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3 |
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| R218 | |
VCC | VOUT | 1 | ||
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| C52 | |||
PST591 |
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(IC13) |
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C56
113 |
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| Parallel I/F | |
| /RESETX |
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| /INIT signal | |
| E05B36 |
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112 |
| 100 |
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/RSTOUTX (IC1) |
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111 | INITRQ |
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/ERRCRPFX |
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30 |
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| 36 |
| XRESET | INT4 |
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| CPU |
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| TMP95C061 |
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| (IC2) |
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Figure 2-17. Reset Circuit Block Diagram
Rev. B |
