MC68302EH16C Freescale Semiconductor, MC68302EH16C Datasheet - Page 358

• Manufacturer Part Number: MC68302EH16C
• Description: IC MPU MULTI-PROTOCOL 132-PQFP
• Manufacturer: Freescale Semiconductor

Specifications of MC68302EH16C

• Processor Type: M683xx 32-Bit
• Speed: 16MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 132-MQFP, 132-PQFP
• Controller Family/series: 68K
• Core Size: 32 Bit
• Ram Memory Size: 1152Byte
• Cpu Speed: 16MHz
• No. Of Timers: 3
• Embedded Interface Type: SCP, TDM
• Digital Ic Case Style: PQFP
• Rohs Compliant: Yes
• Family Name: M68000
• Device Core: ColdFire
• Device Core Size: 32b
• Frequency (max): 16MHz
• Instruction Set Architecture: RISC
• Supply Voltage 1 (typ): 5V
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 132
• Package Type: PQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

MC68302 Applications
The TBD# and RBD# are pointers used by the SCC to show which BD the SCC is currently
using (or which one it will be using next). TBD# and RBD# always sequence around the
queue of BDs in a circular fashion and are initialized to the first BD as shown.
D.3.2 MC68302 Buffer Processing
The communications processor (CP) processes the transmit BDs in a straightforward fash-
ion. Once the transmit side of an SCC is enabled, the CP starts with the first BD in that SCC's
transmit BD table, periodically checking the ready bit to see if that BD is ready. Once that
BD is ready, the CP will process that BD, reading a word at a time from its associated buffer,
doing certain required protocol processing on the data, and moving resultant data to the
SCC transmit FIFO. When the first buffer has been processed, the CP moves on to the next
BD, again waiting for that BD's ready bit to be set. Thus, the CP does no look-ahead BD
processing, nor does it skip over BDs that are not ready. When the CP sees the wrap bit set
in a BD, it goes back to the beginning of the BD table after processing of this BD is complete.
After using a BD, the CP sets its ready bit to not-ready; thus, the CP will not use a BD twice.
The BD must be confirmed by the M68000 core before being used again.
The CP uses the receive BDs in a similar fashion. Once the receive side of an SCC is en-
abled, the CP starts with the first BD in that SCC's receive BD table. Once data arrives from
the serial line into the SCC, the CP performs certain required protocol processing on the
data and moves the resultant data (either by bytes or by words, depending on the protocol)
to the buffer pointed to by the first BD. Use of a BD is complete when there is no more room
D-8
Figure D-4. Transmit and Receive BD Tables
TBD#
TRANSMIT BD TABLE
R = 0
R = 0
R = 0
R = 0
R = 0
R = 0
R = 0
R = 0
MC68302 USER’S MANUAL
7
5
6
3
4
0
1
2
RBD#
RECEIVE BD TABLE
E = 1
E = 1
E = 1
E = 1
E = 1
E = 1
E = 1
E = 1
3
4
5
6
7
0
1
2
MOTOROLA