ST10F276Z5 STMicroelectronics, ST10F276Z5 Datasheet - Page 62

• Manufacturer Part Number: ST10F276Z5
• Description: 16-BIT MICROCONTROLLER WITH MAC UNIT, UP TO 832 KBYTES FLASH MEMORY AND UP TO 68 KBYTES RAM
• Manufacturer: STMicroelectronics

Specifications of ST10F276Z5

• Single Voltage Supply: 5V ±10% (embedded regulator for 1.8 V core supply)

Bootstrap loader
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Error induced by the polling
The code used for the polling is the following:
CAN
bit
Therefore the maximum error at the detection of the communication on CAN pin is:
The error at the detection for the 5
In the worst case, the induced error is 6 CPU clock cycles, so the polling could induce an
error of 6 timer ticks.
Error induced by the baud rate calculation
The content of the timer PT0 counter corresponds to 29 bit times, resulting in the following
equation:
where BRP, Tseg1 and Tseg2 are the field of the CAN Bit Timing register.
The CAN protocol specification recommends to implement a bit time composed of at least 8
time quanta (tq). This recommendation is applied here. Moreover, the maximum bit time
length is 25 tq. To ensure precision, the aim is to have the smallest Bit Rate Prescaler (BRP)
and the maximum number of tq in a bit time.
This gives the following ranges for PT0 according to BRP:
WaitCom:
....
CAN_Boot:
WaitDominantBit:
WaitRecessiveBit:
(1 not taken + 1 taken jumps) + 1 taken jump + 1 bit set: (6) + 6 CPU clock cycles
(1 taken jump) + 1 not taken jump + 1 compare + 1 bit clear: (4) + 6 CPU cycles
JNB P4.5,CAN_Boot
JB
BSET T6R
BSET PWMCON0.0
JMPR cc_UC,WaitRecessiveBit
JB
JNB P4.5,WaitRecessiveBit; wait for 1st dominant bit = Stuff
CMPI1R1,#5
JMPR cc_NE,WaitDominantBit; No, go back to count more
BCLR PWMCON.0
P3.11,WaitCom
P4.5,WaitDominantBit; wait for end of stuff bit
PT0 = 58 x (BRP + 1) X (1 + Tseg1 + Tseg2)
464 x (1 + BRP) ≤ PT0 ≤ 1450 x (1 + BRP)
8 ≤ 1 + Tseg1 + Tseg2 ≤ 25
th
recessive bit is:
; if SOF detected on CAN, then go to
; loader
; Wait for start bit at RxD0
; Start Timer T6
; Start PWM Timer0
; Test if 5th stuff bit detected
; Stop timer
; here the 5th stuff bit is detected:
; PT0 = 29 Bit_Time (25D and 4R)
; (resolution is 1 CPU clk cycle)
ST10F276Z5