MC68908GZ8MFAE Freescale Semiconductor, MC68908GZ8MFAE Datasheet - Page 126

IC MCU 8BIT 8K FLASH 48-LQFP

MC68908GZ8MFAE

Manufacturer Part Number
MC68908GZ8MFAE
Description
IC MCU 8BIT 8K FLASH 48-LQFP
Manufacturer
Freescale Semiconductor
Series
HC08r
Datasheet

Specifications of MC68908GZ8MFAE

Core Processor
HC08
Core Size
8-Bit
Speed
8MHz
Connectivity
CAN, LIN, SCI, SPI
Peripherals
LVD, POR, PWM
Number Of I /o
37
Program Memory Size
8KB (8K x 8)
Program Memory Type
FLASH
Ram Size
1K x 8
Voltage - Supply (vcc/vdd)
3 V ~ 5.5 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 125°C
Package / Case
48-LQFP
Processor Series
M689xx
Core
HC08
Data Bus Width
8 bit
Data Ram Size
1 KB
Interface Type
SPI, SCI, CAN
Maximum Clock Frequency
8 MHz
Number Of Programmable I/os
37
Number Of Timers
2
Operating Supply Voltage
5.5 V
Maximum Operating Temperature
+ 125 C
Mounting Style
SMD/SMT
Development Tools By Supplier
FSICEBASE, M68CBL05AE, DEMO908GZ60E, M68EML08GZE
Minimum Operating Temperature
- 40 C
On-chip Adc
10 bit, 16 Channel
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Eeprom Size
-
Lead Free Status / Rohs Status
 Details
MSCAN08 Controller (MSCAN08)
To transmit a message, the CPU08 has to identify an available transmit buffer which is indicated by a set
transmit buffer empty (TXE) flag in the MSCAN08 transmitter flag register (CTFLG) (see
MSCAN08 Transmitter Flag
The CPU08 then stores the identifier, the control bits and the data content into one of the transmit buffers.
Finally, the buffer has to be flagged ready for transmission by clearing the TXE flag.
The MSCAN08 then will schedule the message for transmission and will signal the successful
transmission of the buffer by setting the TXE flag. A transmit interrupt is generated
can be used to drive the application software to re-load the buffer.
In case more than one buffer is scheduled for transmission when the CAN bus becomes available for
arbitration, the MSCAN08 uses the local priority setting of the three buffers for prioritization. For this
purpose, every transmit buffer has an 8-bit local priority field (PRIO). The application software sets this
field when the message is set up. The local priority reflects the priority of this particular message relative
to the set of messages being emitted from this node. The lowest binary value of the PRIO field is defined
as the highest priority.
The internal scheduling process takes place whenever the MSCAN08 arbitrates for the bus. This is also
the case after the occurrence of a transmission error.
When a high priority message is scheduled by the application software, it may become necessary to abort
a lower priority message being set up in one of the three transmit buffers. As messages that are already
under transmission cannot be aborted, the user has to request the abort by setting the corresponding
abort request flag (ABTRQ) in the transmission control register (CTCR). The MSCAN08 will then grant
the request, if possible, by setting the corresponding abort request acknowledge (ABTAK) and the TXE
flag in order to release the buffer and by generating a transmit interrupt. The transmit interrupt handler
software can tell from the setting of the ABTAK flag whether the message was actually aborted
(ABTAK = 1) or sent (ABTAK = 0).
12.5 Identifier Acceptance Filter
The identifier acceptance registers (CIDAR0–CIDAR3) define the acceptance patterns of the standard or
extended identifier (ID10–ID0 or ID28–ID0). Any of these bits can be marked ‘don’t care’ in the identifier
mask registers (CIDMR0–CIDMR3).
A filter hit is indicated to the application on software by a set RXF (receive buffer full flag, see
MSCAN08 Receiver Flag Register
12.13.9 MSCAN08 Identifier Acceptance Control
clearly identify the filter section that caused the acceptance. They simplify the application software’s task
to identify the cause of the receiver interrupt. In case that more than one hit occurs (two or more filters
match) the lower hit has priority.
A very flexible programmable generic identifier acceptance filter has been introduced to reduce the CPU
interrupt loading. The filter is programmable to operate in four different modes:
1. The transmit interrupt will occur only if not masked. A polling scheme can be applied on TXE also.
126
1. Single identifier acceptance filter, each to be applied to a) the full 29 bits of the extended identifier
and to the following bits of the CAN frame: RTR, IDE, SRR or b) the 11 bits of the standard identifier
plus the RTR and IDE bits of CAN 2.0A/B messages. This mode implements a single filter for a full
length CAN 2.0B compliant extended identifier.
(CIDAR0-3, CIDMR0-3) produces a filter 0 hit.
MC68HC908GZ16 • MC68HC908GZ8 Data Sheet, Rev. 4
Register).
(CRFLG)) and two bits in the identifier acceptance control register (see
Register). These identifier hit flags (IDHIT1 and IDHIT0)
Figure 12-4
shows how the 32-bit filter bank
(1)
Freescale Semiconductor
when TXE is set and
12.13.7
12.13.5

Related parts for MC68908GZ8MFAE