ST72521R9-Auto STMicroelectronics, ST72521R9-Auto Datasheet - Page 191

• Manufacturer Part Number: ST72521R9-Auto
• Description: 8-bit MCU for automotive
• Manufacturer: STMicroelectronics

Specifications of ST72521R9-Auto

• Hdflash Endurance: 100 cycles, data retention 20 years
• Clock Sources: crystal/ceramic resonator oscillators, internal RC oscillator and bypass for external clock
• 4 Power Saving Modes: Halt, Active Halt, Wait and Slow

ST72521xx-Auto
Buffer control/status registers (BCSRx)
Table 104. BCSRx register description
BCSRx
7:4
Bit
3
2
1
0
7
Name
BUSY
LOCK
ACC
RDY
-
Reserved; must be kept at ‘0’
Acceptance Code
Message Ready
Busy Buffer
Lock Buffer
6
Set by hardware with the message identifier of the highest priority filter which
accepted the message stored in the buffer.
0: Match for Filter/Mask0. Possible match for Filter/Mask1.
1: No match for Filter/Mask0 and match for Filter/Mask1.
Reset by hardware when either RDY or RXIF is reset.
Set by hardware to signal that a new error-free message is available (LOCK = 0)
or that a transmission request is pending (LOCK = 1).
Cleared by software when LOCK = 0 to release the buffer and to clear the
corresponding RXIF bit in the Interrupt Status Register.
Cleared by hardware when LOCK = 1 to indicate that the transmission request
has been serviced or cancelled.
Set by hardware when the buffer is being filled (LOCK = 0) or emptied (LOCK = 1)
and reset after the 2nd intermission bit.
Reset by hardware when the buffer is not accessed by the CAN core for
transmission nor reception purposes.
Set by software to lock a buffer. No more message can be received into the buffer
thus preserving its content and making it available for transmission.
Cleared by software to make the buffer available for reception. Cancels any
pending transmission request.
Cleared by hardware once a message has been successfully transmitted provided
the early transmit interrupt mode is on. Left untouched otherwise.
Note that in order to prevent any message corruption or loss of context, LOCK
cannot be set nor reset while BUSY is set. Trying to do so will result in LOCK not
changing state.
Reserved
-
5
Doc ID 17660 Rev 1
4
Function
ACC
RO
3
Controller area network (CAN)
RDY
RC
2
BUSY
RO
1
Reset value: 00h
LOCK
RSC
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