ZHCSR80A June 2009 – January 2023 AMC6821-Q1
PRODUCTION DATA
Bit 7 (MSB) | Bit 6 | Bit 5 | Bit 4 | Bit 3 | Bit 2 | Bit 1 | Bit 0 (LSB) |
---|---|---|---|---|---|---|---|
TACH-DATA7 | TACH-DATA6 | TACH-DATA5 | TACH-DATA4 | TACH-DATA3 | TACH-DATA2 | TACH-DATA1 | TACH-DATA0 |
Bit 7 (MSB) | Bit 6 | Bit 5 | Bit 4 | Bit 3 | Bit 2 | Bit 1 | Bit 0 (LSB) |
---|---|---|---|---|---|---|---|
TACH-DATA15 | TACH-DATA14 | TACH-DATA13 | TACH-DATA12 | TACH-DATA11 | TACH-DATA10 | TACH-DATA9 | TACH-DATA8 |
Bits [TACH-DATA15:TACH-DATA0] are the number of clock pulses counted during one fan revolution and represents the period of the fan revolution (refer to the Fan Speed Measurement section). Reading the TACH data register involves a two-register read. The low byte should be read first. This method causes the high byte to be frozen until both the high and low byte registers have been read from, preventing erroneous TACH readings.