ST STM32L4x6 User Manual

DocID024597 Rev 3 1195/1693
RM0351 Universal synchronous asynchronous receiver transmitter (USART)
1282
Example 2
To obtain 921.6 Kbaud with f
CK
= 48 MHz.
• In case of oversampling by 16:
USARTDIV = 48 000 000/921 600
BRR = USARTDIV = 52d = 34h
• In case of oversampling by 8:
USARTDIV = 2 * 48 000 000/921 600
USARTDIV = 104 (104d = 68h)
BRR[3:0] = USARTDIV[3:0] >> 1 = 8h >> 1 = 4h
BRR = 0x64
Table 193. Error calculation for programmed baud rates at f
CK
= 72MHz in both cases of
oversampling by 16 or by 8
(1)
Baud rate Oversampling by 16 (OVER8 = 0) Oversampling by 8 (OVER8 = 1)
S.No Desired Actual BRR
% Error =
(Calculated -
Desired)B.Rate /
Desired B.Rate
Actual BRR % Error
1 2.4 KBps 2.4 KBps 0x7530 0 2.4 KBps 0xEA60 0
2 9.6 KBps 9.6 KBps 0x1D4C 0 9.6 KBps 0x3A94 0
3 19.2 KBps 19.2 KBps 0xEA6 0 19.2 KBps 0x1D46 0
4 38.4 KBps 38.4 KBps 0x753 0 38.4 KBps 0xEA3 0
5 57.6 KBps 57.6 KBps 0x4E2 0 57.6 KBps 0x9C2 0
6 115.2 KBps 115.2 KBps 0x271 0 115.2 KBps 0x4E1 0
7 230.4 KBps 230.03KBps 0x139 0.16 230.4 KBps 0x270 0
8 460.8 KBps 461.54KBps 0x9C 0.16 460.06KBps 0x134 0.16
9 921.6 KBps 923.08KBps 0x4E 0.16 923.07KBps 0x96 0.16
10 2 MBps 2 MBps 0x24 0 2 MBps 0x44 0
11 3 MBps 3 MBps 0x18 0 3 MBps 0x30 0
12 4MBps 4MBps 0x12 0 4MBps 0x22 0
13 5MBps N.A N.A N.A 4965.51KBps 0x16 0.69
14 6MBps N.A N.A N.A 6MBps 0x14 0
15 7MBps N.A N.A N.A 6857.14KBps 0x12 2
16 9MBps N.A N.A N.A 9MBps 0x10 0
1. The lower the CPU clock the lower the accuracy for a particular baud rate. The upper limit of the achievable baud rate can
be fixed with these data.

ST STM32L4x6 Specifications

General

Brand	ST
Model	STM32L4x6
Category	Microcontrollers
Language	English