89C5121-SK1 Atmel, 89C5121-SK1 Datasheet - Page 88

• Manufacturer Part Number: 89C5121-SK1
• Description: KIT SMART CARD FOR AT89C5121
• Manufacturer: Atmel
• Type: Smart Cardr

Specifications of 89C5121-SK1

• Contents: Board
• For Use With/related Products: AT89C5121
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: T89C5121-SK1; T89C5121-SK1

Reception (Mode 0)
Baud Rate Selection (Mode 0)
88
A/T8xC5121
To start a reception in mode 0, write to SCON register clearing SM0, SM1 and RI bits
and setting the REN bit.
As shown in Figure 40, Clock is pulsed and the LSB (D0) is sampled on the RXD pin.
The D0 bit is then shifted into the shift register. After eight sampling, the MSB (D7) is
shifted into the shift register, and hardware asserts RI bit to indicate a completed recep-
tion. Software can then read the received byte from SBUF register.
Figure 40. Reception Waveforms (Mode 0)
In mode 0, baud rate can be either fixed or variable.
As shown in Figure 41, the selection is done using M0SRC bit in BDRCON register.
Figure 42 gives the baud rate calculation formulas for each baud rate source.
Figure 41. Baud Rate Source Selection (Mode 0)
Figure 42. Baud Rate Formulas (Mode 0)
Write to SCON
Baud_Rate =
a. Fixed Formula
RXD
TXD
RI
CLOCK
CLOCK
F
IBRG
PER
PER
6
Set REN, Clear RI
D0
D1
6
D2
BDRCON.0
M0SRC
D3
0
1
Baud_Rate
BRL = 256
D4
b. Variable Formula
D5
To Serial Port
=
6
6
-
(1-SPD)
(1-SPD)
D6
2
2
SMOD1
SMOD1
32 Baud_Rate
32 (256 -BRL)
D7
4164G–SCR–07/06
F
F
PER
PER