COP8CCR9IMT8/NOPB National Semiconductor, COP8CCR9IMT8/NOPB Datasheet - Page 49

• Manufacturer Part Number: COP8CCR9IMT8/NOPB
• Description: IC MCU EEPROM 8BIT 32K 48-TSSOP
• Manufacturer: National Semiconductor
• Series: COP8™ 8Cr

Specifications of COP8CCR9IMT8/NOPB

• Core Processor: COP8
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: Microwire/Plus (SPI), UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 39
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: FLASH
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 16x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 48-TSSOP
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 20 MHz
• Data Ram Size: 1 KB
• On-chip Adc: 10 bit, 16 channel
• Number Of Programmable I/os: 59
• Number Of Timers: 3
• Height: 0.9 mm
• Interface Type: SPI, USART
• Length: 12.5 mm
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.7 V
• Width: 6.1 mm
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details
• Other names: *COP8CCR9IMT8; *COP8CCR9IMT8/NOPB; COP8CCR9IMT8

14.0 USART
14.6 USART INTERRUPTS
The USART is capable of generating interrupts. Interrupts
are generated on Receive Buffer Full and Transmit Buffer
Empty. Both interrupts have individual interrupt vectors. Two
bytes of program memory space are reserved for each in-
terrupt vector. The two vectors are located at addresses
0xEC to 0xEF Hex in the program memory space. The
interrupts can be individually enabled or disabled using En-
able Transmit Interrupt (ETI) and Enable Receive Interrupt
(ERI) bits in the ENUI register.
The interrupt from the Transmitter is set pending, and re-
mains pending, as long as both the TBMT and ETI bits are
set. To remove this interrupt, software must either clear the
ETI bit or write to the TBUF register (thus clearing the TBMT
bit).
The interrupt from the receiver is set pending, and remains
pending, as long as both the RBFL and ERI bits are set. To
remove this interrupt, software must either clear the ERI bit
or read from the RBUF register (thus clearing the RBFL bit).
(Continued)
FIGURE 23. Framing Formats
49
14.7 BAUD CLOCK GENERATION
The clock inputs to the transmitter and receiver sections of
the USART can be individually selected to come either from
an external source at the CKX pin (port L, pin L1) or from a
source selected in the PSR and BAUD registers. Internally,
the basic baud clock is created from the MCLK through a
two-stage divider chain consisting of a 1-16 (increments of
0.5) prescaler and an 11-bit binary counter (Figure 24). The
divide factors are specified through two read/write registers
shown in Figure 25. Note that the 11-bit Baud Rate Divisor
spills over into the Prescaler Select Register (PSR). PSR is
cleared upon reset.
As shown in Table 18, a Prescaler Factor of 0 corresponds to
NO CLOCK. This condition is the USART power down mode
where the USART clock is turned off for power saving pur-
pose. The user must also turn the USART clock off when a
different baud rate is chosen.
The correspondences between the 5-bit Prescaler Select
and Prescaler factors are shown in Table 18. There are
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