COP8SGR728M8 National Semiconductor, COP8SGR728M8 Datasheet - Page 43

• Manufacturer Part Number: COP8SGR728M8
• Description: 8-Bit Microcontroller IC
• Manufacturer: National Semiconductor
• Series: COP8r

Specifications of COP8SGR728M8

• Controller Family/series: COP8
• Core Size: 8 Bit
• Peak Reflow Compatible (260 C): No
• Leaded Process Compatible: No
• Package: 28SOIC W
• Family Name: COP8
• Maximum Speed: 15 MHz
• Ram Size: 512 Byte
• Program Memory Size: 32 KB
• Operating Supply Voltage: 3.3|5 V
• Data Bus Width: 8 Bit
• Program Memory Type: EPROM
• Number Of Programmable I/os: 40
• Interface Type: USART
• Operating Temperature: -40 to 85 °C
• Number Of Timers: 4
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

12.0 MICROWIRE/PLUS
arrangement with the internal clock source is called the
Master mode of operation. Similarly, operating the
MICROWIRE/PLUS arrangement with an external shift clock
is called the Slave mode of operation.
The CNTRL register is used to configure and control the
MICROWIRE/PLUS mode. To use the MICROWIRE/PLUS,
the MSEL bit in the CNTRL register is set to one. In the
master mode, the SK clock rate is selected by the two bits,
SL0 and SL1, in the CNTRL register. Table 10 details the
different clock rates that may be selected.
12.1 MICROWIRE/PLUS OPERATION
Setting the BUSY bit in the PSW register causes the
MICROWIRE/PLUS to start shifting the data. It gets reset
when eight data bits have been shifted. The user may reset
the BUSY bit by software to allow less than 8 bits to shift. If
Where t
SL1
C
0
0
1
is the instruction cycle clock
TABLE 10. MICROWIRE/PLUS
Master Mode Clock Select
SL0
0
1
x
SK Period
FIGURE 28. MICROWIRE/PLUS Application
(Continued)
2 x t
4 x t
8 x t
C
C
C
43
enabled, an interrupt is generated when eight data bits have
been shifted. The device may enter the MICROWIRE/PLUS
mode either as a Master or as a Slave. Figure 28 shows how
two microcontroller devices and several peripherals may be
interconnected using the MICROWIRE/PLUS arrangements.
The SIO register should only be loaded when the SK clock is
in the idle phase. Loading the SIO register while the SK clock
is in the active phase, will result in undefined data in the SIO
register.
Setting the BUSY flag when the input SK clock is in the
active phase while in the MICROWIRE/PLUS is in the slave
mode may cause the current SK clock for the SIO shift
register to be narrow. For safety, the BUSY flag should only
be set when the input SK clock is in the idle phase.
12.1.1 MICROWIRE/PLUS Master Mode Operation
In the MICROWIRE/PLUS Master mode of operation the
shift clock (SK) is generated internally. The MICROWIRE
Master always initiates all data exchanges. The MSEL bit in
the CNTRL register must be set to enable the SO and SK
functions onto the G Port. The SO and SK pins must also be
selected as outputs by setting appropriate bits in the Port G
configuration register. In the slave mode, the shift clock
stops after 8 clock pulses. Table 11 summarizes the bit
settings required for Master mode of operation.
WARNING
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