Datasheet MAX30101 (Maxim) - 31

MAX30101 High-Sensitivity Pulse Oximeter and Heart-Rate Sensor for Wearable Health
Read Data Format
read the next register after FIFO_DATA, an I2C write For the read operation, two I2C operations must be per- command is necessary to change the location of the read formed. First, the slave ID byte is sent followed by the I2C pointer. register that you wish to read. Then a REPEAT START Figure 10 show the process of reading one byte or mul- (Sr) condition is sent, followed by the read slave ID. The tiple bytes of data. MAX30101 then begins sending data beginning with the An initial write operation is required to send the read reg- register selected in the first operation. The read pointer ister address. increments automatically, so the MAX30101 continues sending data from additional registers in sequential order Data is sent from registers in sequential order, starting until a STOP (P) condition is received. The exception to from the register selected in the initial I2C write operation. this is the FIFO_DATA register, at which the read pointer If the FIFO_DATA register is read, the read pointer will not no longer increments when reading additional bytes. To automatically increment, and subsequent bytes of data will contain the contents of the FIFO. S 1 0 1 0 1 1 1 R/W = 0 ACK A7 A6 A5 A4 A3 A2 A1 A0 ACK SLAVE ID REGISTER ADDRESS Sr 1 0 1 0 1 1 1 R/W ACK D7 D6 D5 D4 D3 D2 D1 D0 NACK P = 1 SLAVE ID DATA BYTE S = START CONDITION ACK = ACKNOWLEDGE BY THE RECEIVER Sr = REPEATED START CONDITION NACK = NOT ACKNOWLEDGE P = STOP CONDITION Figure 10. Reading one byte of data from MAX30101 S 1 0 1 0 1 1 1 R/W = 0 ACK A7 A6 A5 A4 A3 A2 A1 A0 ACK SLAVE ID REGISTER ADDRESS Sr 1 0 1 0 1 1 1 R/W ACK D7 D6 D5 D4 D3 D2 D1 D0 AM = 1 SLAVE ID DATA 1 D7 D6 D5 D4 D3 D2 D1 D0 AM D7 D6 D5 D4 D3 D2 D1 D0 NACK P DATA n-1 DATA n S = START CONDITION ACK = ACKNOWLEDGE BY THE RECEIVER Sr = REPEATED START CONDITION AM = ACKNOWLEDGE BY THE MASTER P = STOP CONDITION NACK = NOT ACKNOWLEDGE Figure 11. Reading multiple bytes of data from the MAX30101 www.maximintegrated.com Maxim Integrated │ 31