153
MC95FG308 / MC95FG208
ABOV Semiconductor Co., Ltd.
serial transfer or stops communication. The following steps continue assuming that I2C does not lose
mastership during first data transfer.
I2C (Master) can choose one of the following cases according to the reception of ACK signal from slave.
1) Master receives ACK signal from slave, so continues data transfer because slave can prepare and transmit
more data to master. Configure ACKEN bit in I2CMR to decide whether I2C ACKnowledges the next data to be
received or not.
2) Master stops data transfer because it receives no ACK signal from slave. In this case, set the STOP bit in
I2CMR.
3) Master transmits repeated START condition due to no ACK signal from slave. In this case, load SLA+R/W
into the I2CDR and set START bit in I2CMR.
After doing one of the actions above, write arbitrary value to I2CSR to release SCL line. In case of 1), move to
step 7. In case of 2), move to step 9 to handle STOP interrupt. In case of 3), move to step 6 after transmitting
the data in I2CDR and if transfer direction bit is ‘0’ go to master transmitter section.
7.
1-byte of data is being received.
8.
This is ACK signal processing stage for data packet transmitted by slave. I2C holds the SCL LOW. When 1-byte
of data is received completely, I2C generates TEND interrupt.
I2C can choose one of the following cases according to the RXACK flag in I2CSR.
1) Master continues receiving data from slave. To do this, set ACKEN bit in I2CMR to ACKnowledge the next
data to be received.
2) Master wants to terminate data transfer when it receives next data by not generating ACK signal. This can be
done by clearing ACKEN bit in I2CMR.
3) Because no ACK signal is detected, master terminates data transfer. In this case, set the STOP bit in I2CMR.
4) No ACK signal is detected, and master transmits repeated START condition. In this case, load SLA+R/W into
the I2CDR and set the START bit in I2CMR.
After doing one of the actions above, write arbitrary value to I2CSR to release SCL line. In case of 1) and 2),
move to step 7. In case of 3), move to step 9 to handle STOP interrupt. In case of 4), move to step 6 after
transmitting the data in I2CDR, and if transfer direction bit is ‘0’ go to master transmitter section.
9.
This is the final step for master receiver function of I2C, handling STOP interrupt. The STOP bit indicates that
data transfer between master and slave is over. To clear I2CSR, write arbitrary value to I2CSR. After this, I2C
enters idle state.
11.9.8.3
Slave Transmitter
To operate I2C in slave transmitter, follow the recommended steps below.
1.
If the main operating clock (SCLK) of the system is slower than that of SCL, load value 0x00 into I2CSDAHR to
make SDA change within one system clock period from the falling edge of SCL. Note that the hold time of SDA
is calculated by SDAH x period of SCLK where SDAH is multiple of number of SCLK coming from I2CSDAHR.
When the hold time of SDA is longer than the period of SCLK, I2C (slave) cannot transmit serial data properly.
Содержание MC95FG208 Series
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Страница 16: ...16 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 3 32 Pin LQFP Package...
Страница 17: ...17 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 4 28 Pin SOP Package...
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Страница 20: ...20 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 7 28 Pin TSSOP Package...
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Страница 22: ...22 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 9 20 Pin TSSOP Package...
Страница 23: ...23 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 10 16 Pin SOP Package...
Страница 24: ...24 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 11 16 Pin TSSOP Package...