Data Sheet
ADuC7019/20/21/22/24/25/26/27/28/29
Table 108. COMSTA1 Register
Network Addressable UART Register Definitions
Name
Address
Default Value
Access
Four additional registers, COMIEN0, COMIEN1, COMIID1, and
COMADR are used in network addressable UART mode only.
COMSTA1
0xFFFF0718
0x00
R
COMSTA1 is a modem status register.
In network address mode, the least significant bit of the COMIEN1
register is the transmitted network address control bit. If set to
1, the device is transmitting an address. If cleared to 0, the
device is transmitting data. For example, the following master-
based code transmits the slave’s address followed by the data:
Table 109. COMSTA1 MMR Bit Descriptions
Bit Name Description
7
6
5
4
3
DCD
RI
DSR
CTS
Data carrier detect.
Ring indicator.
Data set ready.
Clear to send.
COMIEN1 = 0xE7;
//Setting ENAM,
E9BT, E9BR, ETD, NABP
COMTX = 0xA0; // Slave address is 0xA0
DDCD Delta DCD. Set automatically if DCD changed
state since last COMSTA1 read. Cleared automati-
cally by reading COMSTA1.
while(!(0x020==(COMSTA0 & 0x020))){} //
wait for adr tx to finish.
2
1
0
TERI
Trailing edge RI. Set if RI changed from 0 to 1
since COMSTA1 was last read. Cleared
automatically by reading COMSTA1.
COMIEN1 = 0xE6;
to indicate Data is coming
// Clear NAB bit
COMTX = 0x55; // Tx data to slave: 0x55
DDSR Delta DSR. Set automatically if DSR changed state
since COMSTA1 was last read. Cleared
Table 113. COMIEN1 Register
automatically by reading COMSTA1.
Name
Address
Default Value
Access
DCTS
Delta CTS. Set automatically if CTS changed state
since COMSTA1 was last read. Cleared
automatically by reading COMSTA1.
COMIEN1
0xFFFF0720
0x04
R/W
COMIEN1 is an 8-bit network enable register.
Table 110. COMSCR Register
Table 114. COMIEN1 MMR Bit Descriptions
Name
Address
Default Value
Access
Bit Name Description
COMSCR
0xFFFF071C
0x00
R/W
7
6
5
ENAM Network address mode enable bit. Set by user to
enable network address mode. Cleared by user to
disable network address mode.
COMSCR is an 8-bit scratch register used for temporary
storage. It is also used in network addressable UART mode.
E9BT
9-bit transmit enable bit. Set by user to enable
9-bit transmit. ENAM must be set. Cleared by user
to disable 9-bit transmit.
Table 111. COMDIV2 Register
Name
Address
Default Value
Access
E9BR
9-bit receive enable bit. Set by user to enable
9-bit receive. ENAM must be set. Cleared by user
to disable 9-bit receive.
COMDIV2
0xFFFF072C
0x0000
R/W
COMDIV2 is a 16-bit fractional baud divide register.
4
3
ENI
Network interrupt enable bit.
E9BD
Word length. Set for 9-bit data. E9BT has to be
cleared. Cleared for 8-bit data.
Table 112. COMDIV2 MMR Bit Descriptions
Bit
Name
Description
2
ETD
Transmitter pin driver enable bit. Set by user to
enable SOUT pin as an output in slave mode or
multimaster mode. Cleared by user; SOUT is
three-state.
15
FBEN
Fractional baud rate generator enable bit.
Set by user to enable the fractional baud
rate generator. Cleared by user to generate
baud rate using the standard 450 UART
baud rate generator.
1
0
NABP Network address bit. Interrupt polarity bit.
NAB
Network address bit (if NABP = 1). Set by user to
transmit the slave address. Cleared by user to
transmit data.
14:13
12:11
Reserved.
FBM[1:0]
M if FBM = 0, M = 4 (see the Fractional
Divider section).
10:0
FBN[10:0] N (see the Fractional Divider section).
Table 115. COMIID1 Register
Name
Address
Default Value
Access
Network Addressable UART Mode
COMIID1
0xFFFF0724
0x01
R
This mode connects the MicroConverter to a 256-node serial
network, either as a hardware single master or via software in a
multimaster network. Bit 7 (ENAM) of the COMIEN1 register
must be set to enable UART in network addressable mode (see
Table 114). Note that there is no parity check in this mode.
COMIID1 is an 8-bit network interrupt register. Bit 7 to Bit 4
are reserved (see Table 116).
Rev. F | Page 73 of 104
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