ADUC7028 Analog Devices, ADUC7028 Datasheet - Page 69

• Manufacturer Part Number: ADUC7028
• Manufacturer: Analog Devices

Specifications of ADUC7028

• Mcu Core: ARM7 TDMI
• Mcu Speed (mips): 40
• Flash (kbytes): 62Bytes
• Sram (bytes): 8192Bytes
• Gpio Pins: 40
• Adc # Channels: 8

Table 114. COMIID1 MMR Bit Descriptions
Bit 3:1
Status
Bits
000
110
101
011
010
001
000
Note that to receive a network address interrupt, the slave must
ensure that Bit 0 of COMIEN0 (enable receive buffer full interrupt)
is set to 1.
Table 115. COMADR Register
Name
COMADR
COMADR is an 8-bit, read/write network address register that
holds the address checked for by the network addressable
UART. Upon receiving this address, the device interrupts the
processor and/or sets the appropriate status bit in COMIID1.
SERIAL PERIPHERAL INTERFACE
The ADuC7019/20/21/22/24/25/26/27/28/29 integrate a complete
hardware serial peripheral interface (SPI) on-chip. SPI is an
industry standard, synchronous serial interface that allows eight
bits of data to be synchronously transmitted and simultaneously
received, that is, full duplex up to a maximum bit rate of 3.48 Mb,
as shown in Table 116. The SPI interface is not operational with
core clock divider (CD) bits. POWCON[2:0] = 6 or 7 in master
mode.
The SPI port can be configured for master or slave operation
and typically consists of four pins: MISO, MOSI, SCL, and CS .
On the transmit side, the SPITX register (and a TX shift register
outside it) loads data onto the transmit pin (in slave mode,
MISO; in master mode, MOSI). The transmit status bit, Bit 0, in
SPISTA indicates whether there is valid data in the SPITX
register.
Similarly, the receive data path consists of the SPIRX register
(and an RX shift register). SPISTA, Bit 3 indicates whether there
is valid data in the SPIRX register. If valid data in the SPIRX
register is overwritten or if valid data in the RX shift register is
discarded, SPISTA, Bit 5 (the overflow bit) is set.
Bit 0
NINT
1
0
0
0
0
0
0
Address
0xFFFF0728
Priority
2
3
1
2
3
4
Definition
No interrupt
Matching network
address
Address
transmitted,
buffer empty
Receive line status
interrupt
Receive buffer full
interrupt
Transmit buffer
empty interrupt
Modem status
interrupt
Default Value
0xAA
Clearing
Operation
Read COMRX
Write data to
COMTX or
read COMIID0
Read
COMSTA0
Read COMRX
Write data to
COMTX or
read COMIID0
Read
COMSTA1
Access
R/W
Rev. D | Page 69 of 96
MISO (Master In, Slave Out) Pin
The MISO pin is configured as an input line in master mode
and an output line in slave mode. The MISO line on the master
(data in) should be connected to the MISO line in the slave
device (data out). The data is transferred as byte wide (8-bit)
serial data, MSB first.
MOSI (Master Out, Slave In) Pin
The MOSI pin is configured as an output line in master mode
and an input line in slave mode. The MOSI line on the master
(data out) should be connected to the MOSI line in the slave
device (data in). The data is transferred as byte wide (8-bit)
serial data, MSB first.
SCL (Serial Clock I/O) Pin
The master serial clock (SCL) is used to synchronize the data
being transmitted and received through the MOSI SCL period.
Therefore, a byte is transmitted/received after eight SCL periods.
The SCL pin is configured as an output in master mode and as
an input in slave mode.
In master mode, the polarity and phase of the clock are
controlled by the SPICON register, and the bit rate is defined in
the SPIDIV register as follows:
The maximum speed of the SPI clock is dependent on the clock
divider bits and is summarized in Table 116.
Table 116. SPI Speed vs. Clock Divider Bits in Master Mode
CD Bits
SPIDIV in Hex
SPI dpeed
in MHz
In slave mode, the SPICON register must be configured with
the phase and polarity of the expected input clock. The slave
accepts data from an external master up to 10.4 Mb at CD = 0.
The formula to determine the maximum speed is as follows:
In both master and slave modes, data is transmitted on one edge
of the SCL signal and sampled on the other. Therefore, it is
important that the polarity and phase be configured the same
for the master and slave devices.
Chip Select ( CS Input) Pin
In SPI slave mode, a transfer is initiated by the assertion of CS ,
which is an active low input signal. The SPI port then transmits
and receives 8-bit data until the transfer is concluded by
deassertion of CS . In slave mode, CS is always an input.
ADuC7019/20/21/22/24/25/26/27/28/29
f
f
SERIAL
SERIAL
CLOCK
CLOCK
0
0x05
3.482
=
=
2
f
HCLK
×
4
1 (
1
0x0B
1.741
+
f
UCLK
SPIDIV
2
0x17
0.870
)
3
0x2F
0.435
4
0x5F
0.218
5
0xBF
0.109