ST7LITE49K2 STMicroelectronics, ST7LITE49K2 Datasheet - Page 145

• Manufacturer Part Number: ST7LITE49K2
• Description: 8-bit MCU
• Manufacturer: STMicroelectronics

Specifications of ST7LITE49K2

• 8 Kbytes Single Voltage Extended Flash (xflash) Program Memory With Read-out Protection In-circuit Programming And In-application Programming (icp And Iap) Endurance: 10K write/erase cycles guaranteed Data retention
• 256 Bytes Data Eeprom With Read-out Protection. 300k Write/erase Cycles Guaranteed, Data Retention: 20 years at 55 °C.
• Clock Sources: Internal trimmable 8 MHz RC oscillator, auto-wakeup internal low power - low frequency oscillator, crystal/ceramic resonator or external clock
• Five Power Saving Modes: Halt, Active-halt, Auto-wakeup from Halt, Wait and Slow

ST7LITE49K2
Note:
Master transmitter
Following the address transmission and after SR1 register has been read, the master
sends bytes from the DR register to the SDA line via the internal shift register.
The master waits for a read of the SR1 register followed by a write in the DR register,
holding the SCL line low (see
When the acknowledge bit is received, the interface sets EVF and BTF bits with an interrupt
if the ITE bit is set.
To close the communication: after writing the last byte to the DR register, set the STOP bit to
generate the Stop condition. The interface goes automatically back to slave mode (M/SL bit
cleared).
Error cases
●
●
●
In all these cases, the SCL line is not held low; however, the SDA line can remain low if the
last bits transmitted are all 0. It is then necessary to release both lines by software. The SCL
line is not held low while AF=1 but by other flags (SB or BTF) that are set at the same time.
BERR: Detection of a Stop or a Start condition during a byte transfer. In this case, the
EVF and BERR bits are set by hardware with an interrupt if ITE is set.
Note that BERR will not be set if an error is detected during the first pulse of each 9-bit
transaction:
Single Master mode
If a Start or Stop is issued during the first pulse of a 9-bit transaction, the BERR flag will
not be set and transfer will continue however the BUSY flag will be reset. To work
around this, slave devices should issue a NACK when they receive a misplaced Start or
Stop. The reception of a NACK or BUSY by the master in the middle of communication
gives the possibility to reinitiate transmission.
Multimaster mode
Normally the BERR bit would be set whenever unauthorized transmission takes place
while transfer is already in progress. However, an issue will arise if an external master
generates an unauthorized Start or Stop while the I
9-bit transaction. It is possible to work around this by polling the BUSY bit during I
master mode transmission. The resetting of the BUSY bit can then be handled in a
similar manner as the BERR flag being set.
AF: Detection of a non-acknowledge bit. In this case, the EVF and AF bits are set by
hardware with an interrupt if the ITE bit is set. To resume, set the Start or Stop bit.
The AF bit is cleared by reading the I2CSR2 register. However, if read before the
completion of the transmission, the AF flag will be set again, thus possibly generating a
new interrupt. Software must ensure either that the SCL line is back at 0 before reading
the SR2 register, or be able to correctly handle a second interrupt during the 9th pulse
of a transmitted byte.
ARLO: Detection of an arbitration lost condition.
In this case the ARLO bit is set by hardware (with an interrupt if the ITE bit is set and
the interface goes automatically back to slave mode (the M/SL bit is cleared).
Figure 71
Transfer sequencing EV8).
2
C master is on the first pulse of a
On-chip peripherals
145/245
2
C