71m6521be Maxim Integrated Products, Inc., 71m6521be Datasheet - Page 23

• Manufacturer Part Number: 71m6521be
• Description: Energy Meter Ic
• Manufacturer: Maxim Integrated Products, Inc.

The 71M6521BE has several UART-related registers for the control and buffering of serial data. All UART transfers are pro-
grammable for parity enable, parity, 2 stop bits/1 stop bit and XON/XOFF options for variable communication baud rates from
300 to 38400 bps. Table 12 shows how the baud rates are calculated. Table 13 shows the selectable UART operation modes.
Note:
SFR PCON.
Mode 0
Mode 1
Mode 2
Mode 3
handshake signals for inter-processor communication in multi-processor systems.
Serial Interface 0 Control Register (S0CON).
The function of the UART0 depends on the setting of the Serial Port Control Register S0CON.
Serial Interface 1 Control Register (S1CON).
The function of the serial port depends on the setting of the Serial Port Control Register S1CON.
V1.0
S0REL
UART0
UART1
Parity of serial data is available through the P flag of the accumulator. Seven-bit serial modes with parity, such as
those used by the FLAG protocol, can be simulated by setting and reading bit 7 of 8-bit output data. Seven-bit serial
modes without parity can be simulated by setting bit 7 to a constant 1. 8-bit serial modes with parity can be simulated
by setting and reading the 9
SFRs for transmit and RB81 (S1CON.2) for receive operations. SM20 (S0CON.5) and SM21 (S1CON.5) can be used as
TH1
and
MSB
MSB
is the high byte of timer 1
rate (internal baud rate generator or timer 1)
S1REL
Start bit, 8 data bits, parity, stop bit, variable
Start bit, 8 data bits, stop bit, variable baud
SM0
baud rate (internal baud rate generator or
Start bit, 8 data bits, parity, stop bit, fixed
SM
baud rate 1/32 or 1/64 of f
are 10-bit values derived by combining bits from the respective timer reload registers.
2
SMOD
SM1
-
* f
CKMPU
UART 0
timer 1)
Using Timer 1
N/A
th
.
SM20
SM21
bit, using the control bits TB80 (S0CON.3) and TB81 (S1CON.3) in the S0CON and S1CON
© 2005-2008 TERIDIAN Semiconductor Corporation
/ (384 * (256-TH1))
N/A
Table 12: Baud Rate Generation
Table 14: The S0CON Register
Table 15: The S1CON register
CKMPU
REN0
REN1
Table 13: UART Modes
TB80
TB81
Start bit, 8 data bits, parity, stop bit, variable baud
Start bit, 8 data bits, stop bit, variable baud rate
Using Internal Baud Rate Generator
RB80
RB81
2
rate (internal baud rate generator)
SMOD
(internal baud rate generator)
f
CKMPU
* f
CKMPU
/(32 * (2
TI0
TI1
UART 1
/(64 * (2
Energy Meter IC
N/A
N/A
10
-S1REL))
RI0
RI1
10
LSB
LSB
-S0REL))
71M6521BE
DATA SHEET
SMOD
is the
JANUARY 2008
Page: 23 of 97
SMOD
bit in the