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1 | Kernel driver w1_ds28e04 |
2 | ======================== | |
3 | ||
4 | Supported chips: | |
5 | * Maxim DS28E04-100 4096-Bit Addressable 1-Wire EEPROM with PIO | |
6 | ||
7 | supported family codes: | |
8 | W1_FAMILY_DS28E04 0x1C | |
9 | ||
10 | Author: Markus Franke, <franke.m@sebakmt.com> <franm@hrz.tu-chemnitz.de> | |
11 | ||
12 | Description | |
13 | ----------- | |
14 | ||
15 | Support is provided through the sysfs files "eeprom" and "pio". CRC checking | |
16 | during memory accesses can optionally be enabled/disabled via the device | |
17 | attribute "crccheck". The strong pull-up can optionally be enabled/disabled | |
18 | via the module parameter "w1_strong_pullup". | |
19 | ||
20 | Memory Access | |
21 | ||
22 | A read operation on the "eeprom" file reads the given amount of bytes | |
23 | from the EEPROM of the DS28E04. | |
24 | ||
25 | A write operation on the "eeprom" file writes the given byte sequence | |
26 | to the EEPROM of the DS28E04. If CRC checking mode is enabled only | |
f884ab15 | 27 | fully aligned blocks of 32 bytes with valid CRC16 values (in bytes 30 |
fbf7f7b4 MF |
28 | and 31) are allowed to be written. |
29 | ||
30 | PIO Access | |
31 | ||
32 | The 2 PIOs of the DS28E04-100 are accessible via the "pio" sysfs file. | |
33 | ||
34 | The current status of the PIO's is returned as an 8 bit value. Bit 0/1 | |
35 | represent the state of PIO_0/PIO_1. Bits 2..7 do not care. The PIO's are | |
36 | driven low-active, i.e. the driver delivers/expects low-active values. |