126
MC95FG308 / MC95FG208
ABOV Semiconductor Co., Ltd.
11.7.3 Clock Generation
Figure 11.40
Clock Generation Block Diagram
The Clock generation logic generates the base clock for the Transmitter and Receiver. The USART supports four
modes of clock operation and those are Normal Asynchronous, Double Speed Asynchronous, Master Synchronous
and Slave Synchronous. The clock generation scheme for Master SPI and Slave SPI mode is the same as Master
Synchronous and Slave Synchronous operation mode. The UMSELn bit in UCTRLx1 register selects between
asynchronous and synchronous operation. Asynchronous Double Speed mode is controlled by the U2X bit in the
UCTRLx2 register. The MASTER bit in UCTRLx2 register controls whether the clock source is internal (Master mode,
output port) or external (Slave mode, input port). The XCK pin is only active when the USART operates in
Synchronous or SPI mode.
Table below contains equations for calculating the baud rate (in bps).
Operating Mode
Equation for Calculating Baud Rate
Asynchronous Normal Mode (U2X=0)
Baud Rate =
fSCLK
16( 1)
Asynchronous Double Speed Mode (U2X=1)
Baud Rate =
fSCLK
8( 1)
Synchronous or SPI Master Mode
Baud Rate =
fSCLK
2( 1)
Table 11.14
Equations for Calculating Baud Rate Register Setting
XCK
Prescaling
Up-Counter
UBAUD
/2
/8
Sync Register
M
U
X
M
U
X
M
U
X
M
U
X
/2
Edge
Detector
SCLK
f
SCLK
(UBAUD+1)
txclk
rxclk
UMSEL0
U2X
MASTER
UCPOL
Содержание MC95FG208 Series
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Страница 19: ...19 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 6 28 Pin SOP Package...
Страница 20: ...20 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 7 28 Pin TSSOP Package...
Страница 21: ...21 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 8 20 Pin SOP Package...
Страница 22: ...22 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 9 20 Pin TSSOP Package...
Страница 23: ...23 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 10 16 Pin SOP Package...
Страница 24: ...24 MC95FG308 MC95FG208 ABOV Semiconductor Co Ltd Figure 4 11 16 Pin TSSOP Package...