ST72521R9 STMicroelectronics, ST72521R9 Datasheet - Page 138

• Manufacturer Part Number: ST72521R9
• Description: 8-BIT MCU WITH NESTED INTERRUPTS, FLASH, 10-BIT ADC, FIVE TIMERS, SPI, SCI, I2C, CAN INTERFACE
• Manufacturer: STMicroelectronics

Specifications of ST72521R9

• Hdflash Endurance: 100 cycles, data retention
• Clock Sources: crystal/ceramic resonator oscillators, internal RC oscillator 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

ST72F521, ST72521B
CONTROLLER AREA NETWORK (Cont’d)
CONTROL/STATUS REGISTER (CSR)
Read/Write
Reset Value: 00h
Bit 6 = BOFF Bus-Off State
−
Set by hardware to indicate that the node is in bus-
off state, i.e. the Transmit Error Counter exceeds
255.
Reset by hardware to indicate that the node is in-
volved in bus activities.
Bit 5 = EPSV Error Passive State
−
Set by hardware to indicate that the node is error
passive.
Reset by hardware to indicate that the node is either
error active (BOFF = 0) or bus-off.
Bit 4 = SRTE Simultaneous Receive/Transmit En-
able
Set by software to enable simultaneous transmis-
sion and reception of a message passing the ac-
ceptance filtering. Allows to check the integrity of
the communication path.
Reset by software to discard all messages trans-
mitted by the node. Allows remote and data frames
to share the same identifier.
138/215
Read Only
Read Only
7
0
−
BOFF EPSV SRTE NRTX FSYN WKPS
Read/Set/Clear
RUN
0
Bit 3 = NRTX No Retransmission
−
Set by software to disable the retransmission of un-
successful messages. It does not stop transmission
in case of Arbitration Lost.
Cleared by software to enable retransmission of
messages until success is met.
Bit 2 = FSYN Fast Synchronization
−
Set by software to enable a fast resynchronization
when leaving standby mode, i.e. wait for only 11 re-
cessive bits in a row.
Cleared by software to enable the standard resyn-
chronization when leaving standby mode, i.e. wait
for 128 sequences of 11 recessive bits.
Bit 1 = WKPS Wake-up Pulse
−
Set by software to generate a dominant pulse when
leaving standby mode.
Cleared by software for no dominant wake-up
pulse.
Bit 0 = RUN CAN Enable
−
Set by software to leave standby mode after 128 se-
quences of 11 recessive bits or just 11 recessive
bits if FSYN is set.
Cleared by software to request a switch to the
standby or low-power mode as soon as any on-go-
ing transfer is complete. Read-back as 1 in the
meantime to enable proper signalling of the standby
state. The CPU clock may therefore be safely
switched OFF whenever RUN is read as 0.
Read/Set/Clear
Read/Set/Clear
Read/Set/Clear
Read/Set/Clear