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1 | ------------------------------------------------------------------------------- |
2 | Epson 8564JE I2C RTC | |
3 | ------------------------------------------------------------------------------- | |
4 | ||
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5 | This an example capture of I2C traffic from/to an Epson 8564JE I2C RTC chip, |
6 | which has a slave address of 0x51 (or 0xa2, if the read/write bit is included). | |
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7 | |
8 | ||
9 | Logic analyzer setup | |
10 | -------------------- | |
11 | ||
12 | The logic analyzer used for capturing was a ChronoVu LA8 at a sample rate | |
13 | of 1MHz. The logic analyzer probes were connected to the RTC chip like this: | |
14 | ||
15 | Probe RTC chip pin | |
16 | ------------------------ | |
17 | 0 (green) SCL | |
709737bd | 18 | 1 (orange) SDA |
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19 | |
20 | ||
21 | Data | |
22 | ---- | |
23 | ||
24 | The device talking to the RTC was doing the following in an infinite loop: | |
25 | ||
26 | - Set the RTC to a specific date/time (Nov 22, 2011 - 04:03:54, weekday = 2). | |
27 | ||
28 | - Read back the current time from the RTC. | |
29 | ||
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30 | This is what the decoded data should look like: |
31 | ||
32 | - Setting the date/time: | |
33 | S Wr:0xa2 A 0x02 A 0x54 A 0x03 A 0x04 A 0x22 A 0x02 A 0x11 A 0x11 A P | |
34 | ||
35 | - Reading the current date/time: | |
36 | S Wr:0xa2 A 0x02 A Sr Rd:0xa3 A 0x54 A 0x03 A 0x44 A 0x62 A 0x52 A | |
37 | 0x51 A 0x11 N P | |
38 | ||
49d0ad90 | 39 | - The abbreviations used above: S = Start, Wr = Write, A = ACK, P = Stop, |
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40 | Sr = Repeated start, Rd = Read, N = NACK |
41 | ||
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42 | The sigrok command line used was: |
43 | ||
44 | sigrok-cli -d 0:samplerate=1mhz --samples 8388608 \ | |
709737bd | 45 | -p '1=SCL,2=SDA' -o rtc_epson_8564je.sr |
e63e73d9 | 46 |