89C5121-SK1 Atmel, 89C5121-SK1 Datasheet - Page 90

• 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

Framing Error Detection
(Modes 1, 2 and 3)
Baud Rate Selection (Modes 1
and 3)
Figure 47. Baud Rate Source Selection (Modes 1 and 3)
90
A/T8xC5121
CLOCK
CLOCK
IBRG
T1
BDRCON.2
RBCK
0
1
Framing error detection is provided for the three asynchronous modes. To enable the
framing bit error detection feature, set SMOD0 bit in PCON register as shown in
Figure 46.
When this feature is enabled, the receiver checks each incoming data frame for a valid
stop bit. An invalid stop bit may result from noise on the serial lines or from simultaneous
transmission by two devices. If a valid stop bit is not found, the software sets FE bit in
SCON register.
Software may examine FE bit after each reception to check for data errors. Once set,
only software or a chip reset clear FE bit. Subsequently received frames with valid stop
bits cannot clear FE bit. When the framing error detection feature is enabled, RI rises on
stop bit instead of the last data bit as detailed in Figure 36.
Figure 46. Framing Error Block Diagram
In modes 1 and 3, the Baud Rate is derived either from the Timer 1 or the Internal Baud
Rate Generator and allows different baud rate in reception and transmission.
As shown in Figure 47 the selection is done using RBCK and TBCK bits in BDRCON
register.
Figure 48 gives the baud rate calculation formulas for each baud rate source while
Table 65 details Internal Baud Rate Generator configuration for different peripheral
clock frequencies and giving baud rates closer to the standard baud rates.
Figure 48. Baud Rate Formulas (Modes 1 and 3)
Baud_Rate
16
BRL = 256
To Serial
Reception Port
a. BRG Formula
=
6
6
-
(1-SPD
(1-SPD)
Framing Error
Controller
2
2
)
SMOD1
SMOD1
32 (256 -BRL)
32 Baud_Rate
F
F
PER
PER
CLOCK
CLOCK
IBRG
T1
FE
SM0
BDRCON.3
TBCK
SMOD0
PCON.6
0
1
1
0
16
Baud_Rate
SM0/FE
SCON.7
TH1 = 256
To serial
Transmission Port
b. T1 Formula
=
6 32 (256 -TH1)
192 Baud_Rate
-
2
2
SMOD1
SMOD1
4164G–SCR–07/06
F
F
PER
PER