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Philips Semiconductors | User’s Manual - Preliminary - | |
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P89LPC906/907/908 |
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| Reset |
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RTCH |
| RTCL | RTC Reset |
| XTAL2 XTAL1 |
Reload on underflow |
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| Low freq. |
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| Med. freq. |
MSB |
| LSB |
| High freq. | |
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| CCLK | |
Wake up from |
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| Int. Osc’s |
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| RTCF | RTCEN | RTCS1 | RTCS2 | |
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Interrupt | ERTC | RTC underflow flag | RTC Enable | RTC clk select | |
if enabled |
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(shared w. WDT) |
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Figure 6-1: Real-time clock/system timer Block Diagram
Table 6-1: Real-time Clock/System Timer Clock Source - P89LPC906
FOSC2 | FOSC1 | FOSC0 | RTCS1:0 |
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(UCFG1.2) | (UCFG1.1) | (UCFG1.0) | CCLK Frequency | RTC Clock Frequency | |
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| 00 |
| High frequency crystal |
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| 01 |
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| (XCLK) | |
0 | 0 | 0 |
| High frequency crystal/DIVM | |
10 |
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| 11 |
| High frequency crystal/DIVM |
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| (CCLK) | |
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| 00 |
| Medium frequency crystal |
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| 01 |
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| (XCLK) | |
0 | 0 | 1 |
| Medium frequency crystal/DIVM | |
10 |
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| 11 |
| Medium frequency crystal/ |
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| DIVM (CCLK) | |
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| 00 |
| Low frequency crystal |
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| 01 |
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| (XCLK) | |
0 | 1 | 0 |
| Low frequency crystal/DIVM | |
10 |
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| 11 |
| Low frequency crystal/DIVM |
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| (CCLK) | |
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2003 Dec 8 | 48 |