MC68332GCEH20 Freescale Semiconductor, MC68332GCEH20 Datasheet - Page 68

• Manufacturer Part Number: MC68332GCEH20
• Description: IC MCU 32BIT 20MHZ 132-PQFP
• Manufacturer: Freescale Semiconductor
• Series: M683xxr

Specifications of MC68332GCEH20

• Core Processor: CPU32
• Core Size: 32-Bit
• Speed: 20MHz
• Connectivity: EBI/EMI, SCI, SPI, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 15
• Program Memory Type: ROMless
• Ram Size: 2K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 132-QFP
• Controller Family/series: 68K
• No. Of I/o's: 15
• Ram Memory Size: 2KB
• Cpu Speed: 20MHz
• No. Of Timers: 1
• Embedded Interface Type: QSPI, SCI, UART
• Digital Ic Case Style: PQFP
• Rohs Compliant: Yes
• Data Bus Width: 32 bit
• Data Ram Size: 2 KB
• Interface Type: QSPI, SCI, UART
• Maximum Clock Frequency: 20 MHz
• Number Of Programmable I/os: 15
• Number Of Timers: 16
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Program Memory Size: -
• Data Converters: -
• Lead Free Status / Rohs Status: Details

4.5.4.1 Breakpoint Acknowledge Cycle
4.5.4.1.1 Software Breakpoints
4.5.4.1.2 Hardware Breakpoints
4-28
Breakpoints stop program execution at a predefined point during system development.
Breakpoints can be used alone or in conjunction with the background debugging
mode. The following paragraphs discuss breakpoint processing when background de-
bugging mode is not enabled. See SECTION 5 CENTRAL PROCESSING UNIT for
more information on exception processing and the background debugging mode.
In M68300 microcontrollers, both hardware and software can initiate breakpoints.
The CPU32 BKPT instruction allows the user to insert breakpoints through software.
The CPU responds to this instruction by initiating a breakpoint-acknowledge read cy-
cle in CPU space. It places the breakpoint acknowledge (%0000) code on AD-
DR[19:16], the breakpoint number (bits [2:0] of the BKPT opcode) in ADDR[4:2], and
%0 (indicating a software breakpoint) on ADDR1.
The external breakpoint circuitry decodes the function code and address lines and re-
sponds by either asserting BERR or placing an instruction word on the data bus and
asserting DSACK.
If the bus cycle is terminated by DSACK, the CPU32 reads the instruction on the data
bus and inserts the instruction into the pipeline. (For 8-bit ports, this instruction fetch
may require two read cycles.)
If the bus cycle is terminated by BERR, the CPU32 then performs illegal-instruction
exception processing: it acquires the number of the illegal-instruction exception vector,
computes the vector address from this number, loads the content of the vector address
into the PC, and jumps to the exception handler routine at that address.
Assertion of the BKPT input initiates a hardware breakpoint. The CPU responds by ini-
tiating a breakpoint-acknowledge read cycle in CPU space. It places $00001E on the
address bus. (The breakpoint acknowledge code of %0000 is placed on ADDR[19:16],
the breakpoint number value of %111 is placed on ADDR[4:2], and ADDR1 is set to
one, indicating a hardware breakpoint.)
The external breakpoint circuitry decodes the function code and address lines, places
an instruction word on the data bus, and asserts BERR. The CPU then performs hard-
ware breakpoint exception processing: it acquires the number of the hardware break-
point exception vector, computes the vector address from this number, loads the
content of the vector address into the PC, and jumps to the exception handler routine
at that address. If the external device asserts DSACK rather than BERR, the CPU ig-
nores the breakpoint and continues processing.
When BKPT assertion is synchronized with an instruction prefetch, processing of the
breakpoint exception occurs at the end of that instruction. The prefetched instruction
is “tagged” with the breakpoint when it enters the instruction pipeline, and the break-
point exception occurs after the instruction executes. If the pipeline is flushed before
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MC68332