ST72321AR6 STMicroelectronics, ST72321AR6 Datasheet - Page 109

• Manufacturer Part Number: ST72321AR6
• Description: 8-BIT MCU WITH NESTED INTERRUPTS, FLASH,10-BIT ADC, FIVE TIMERS, SPI, SCI, I2C INTERFACE
• Manufacturer: STMicroelectronics

Specifications of ST72321AR6

• Hdflash Endurance: 100 cycles, data retention
• Clock Sources: crystal/ceramic resonator oscillators, internal RC oscillator, clock security system and bypass for external clock
• Four Power Saving Modes: Halt, Active-Halt,Wait and Slow
• Main Clock Controller With: Real time base, Beep and Clock-out capabilities
• Two 16-bit Timers With: 2 input captures, 2 output compares, external clock input on one timer, PWM and pulse generator modes
• 8-bit Pwm Auto-reload Timer With: 2 input captures, 4 PWM outputs, output compare and time base interrupt, external clock with event detector

SERIAL COMMUNICATIONS INTERFACE (Cont’d)
10.6.7 Register Description
STATUS REGISTER (SCISR)
Read Only
Reset Value: 1100 0000 (C0h)
Bit 7 = TDRE Transmit data register empty.
This bit is set by hardware when the content of the
TDR register has been transferred into the shift
register. An interrupt is generated if the TIE bit = 1
in the SCICR2 register. It is cleared by a software
sequence (an access to the SCISR register fol-
lowed by a write to the SCIDR register).
0: Data is not transferred to the shift register
1: Data is transferred to the shift register
Note: Data is not transferred to the shift register
unless the TDRE bit is cleared.
Bit 6 = TC Transmission complete.
This bit is set by hardware when transmission of a
frame containing Data is complete. An interrupt is
generated if TCIE = 1 in the SCICR2 register. It is
cleared by a software sequence (an access to the
SCISR register followed by a write to the SCIDR
register).
0: Transmission is not complete
1: Transmission is complete
Note: TC is not set after the transmission of a Pre-
amble or a Break.
Bit 5 = RDRF Received data ready flag.
This bit is set by hardware when the content of the
RDR register has been transferred to the SCIDR
register. An interrupt is generated if RIE = 1 in the
SCICR2 register. It is cleared by a software se-
quence (an access to the SCISR register followed
by a read to the SCIDR register).
0: Data is not received
1: Received data is ready to be read
Bit 4 = IDLE Idle line detect.
This bit is set by hardware when a Idle Line is de-
tected. An interrupt is generated if the ILIE = 1 in
the SCICR2 register. It is cleared by a software se-
quence (an access to the SCISR register followed
by a read to the SCIDR register).
0: No Idle Line is detected
1: Idle Line is detected
TDRE
7
TC
RDRF
IDLE
OR
NF
FE
PE
0
Note: The IDLE bit is not set again until the RDRF
bit has been set itself (that is, a new idle line oc-
curs).
Bit 3 = OR Overrun error.
This bit is set by hardware when the word currently
being received in the shift register is ready to be
transferred into the RDR register while RDRF = 1.
An interrupt is generated if RIE = 1 in the SCICR2
register. It is cleared by a software sequence (an
access to the SCISR register followed by a read to
the SCIDR register).
0: No Overrun error
1: Overrun error is detected
Note: When this bit is set RDR register content is
not lost but the shift register is overwritten.
Bit 2 = NF Noise flag.
This bit is set by hardware when noise is detected
on a received frame. It is cleared by a software se-
quence (an access to the SCISR register followed
by a read to the SCIDR register).
0: No noise is detected
1: Noise is detected
Note: This bit does not generate interrupt as it ap-
pears at the same time as the RDRF bit which it-
self generates an interrupt.
Bit 1 = FE Framing error.
This bit is set by hardware when a de-synchroniza-
tion, excessive noise or a break character is de-
tected. It is cleared by a software sequence (an
access to the SCISR register followed by a read to
the SCIDR register).
0: No Framing error is detected
1: Framing error or break character is detected
Note: This bit does not generate interrupt as it ap-
pears at the same time as the RDRF bit which it-
self generates an interrupt. If the word currently
being transferred causes both frame error and
overrun error, it will be transferred and only the OR
bit will be set.
Bit 0 = PE Parity error.
This bit is set by hardware when a parity error oc-
curs in receiver mode. It is cleared by a software
sequence (a read to the status register followed by
an access to the SCIDR data register). An inter-
rupt is generated if PIE = 1 in the SCICR1 register.
0: No parity error
1: Parity error
ST72321Rx ST72321ARx ST72321Jx
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