DSPIC30F5011-20I/PTG Microchip Technology, DSPIC30F5011-20I/PTG Datasheet - Page 125

• Manufacturer Part Number: DSPIC30F5011-20I/PTG
• Description: IC, DSC, 16BIT, 66KB, 40MHZ 5.5V TQFP-64
• Manufacturer: Microchip Technology
• Series: DsPIC30Fr

Specifications of DSPIC30F5011-20I/PTG

• Core Frequency: 40MHz
• Core Supply Voltage: 5.5V
• Embedded Interface Type: CAN, I2C, SPI, UART
• No. Of I/o's: 52
• Flash Memory Size: 66KB
• Supply Voltage Range: 2.5V To 5.5V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

18.3.14
The amount of data that is buffered between interrupts
is determined by the buffer length (BLEN<1:0>) control
bits in the DCICON1 SFR. The size of the transmit and
receive buffers may be varied from 1 to 4 data words
using the BLEN control bits. The BLEN control bits are
compared to the current value of the DCI buffer control
unit address counter. When the 2 LSbs of the DCI
address counter match the BLEN<1:0> value, the
buffer control unit will be reset to ‘0’. In addition, the
contents of the receive shadow registers are
transferred to the receive buffer registers and the
contents of the transmit buffer registers are transferred
to the transmit shadow registers.
18.3.15
There is no direct coupling between the position of the
AGU address pointer and the data frame boundaries.
This means that there will be an implied assignment of
each transmit and receive buffer that is a function of the
BLEN control bits and the number of enabled data slots
via the TSE and RSE control bits.
As an example, assume that a 4-word data frame is
chosen and that we want to transmit on all four time
slots in the frame. This configuration would be
established by setting the TSE0, TSE1, TSE2 and
TSE3 control bits in the TSCON SFR. With this module
setup, the TXBUF0 register would be naturally
assigned to slot #0, the TXBUF1 register would be
naturally assigned to slot #1, and so on.
© 2008 Microchip Technology Inc.
Note:
BUFFER ALIGNMENT WITH DATA
FRAMES
When more than four time slots are active
within a data frame, the user code must
keep track of which time slots are to be
read/written at each interrupt. In some
cases,
transmit/receive
respective slot assignments could be lost.
Examples of such cases include an
emulation breakpoint or a hardware trap.
In these situations, the user should poll the
SLOT status bits to determine what data
should be loaded into the buffer registers
to resynchronize the software with the DCI
module.
BUFFER LENGTH CONTROL
the
alignment
buffers
and
between
their
18.3.16
There are two transmit status bits in the DCISTAT SFR.
The TMPTY bit is set when the contents of the transmit
buffer registers are transferred to the transmit shadow
registers. The TMPTY bit may be polled in software to
determine when the transmit buffer registers may be
written. The TMPTY bit is cleared automatically by the
hardware when a write to one of the four transmit
buffers occurs.
The TUNF bit is read-only and indicates that a transmit
underflow has occurred for at least one of the transmit
buffer registers that is in use. The TUNF bit is set at the
time the transmit buffer registers are transferred to the
transmit shadow registers. The TUNF Status bit is
cleared automatically when the buffer register that
underflowed is written by the CPU.
18.3.17
There are two receive status bits in the DCISTAT SFR.
The RFUL Status bit is read-only and indicates that
new data is available in the receive buffers. The RFUL
bit is cleared automatically when all receive buffers in
use have been read by the CPU.
The ROV Status bit is read-only and indicates that a
receive overflow has occurred for at least one of the
receive buffer locations. A receive overflow occurs
when the buffer location is not read by the CPU before
new data is transferred from the shadow registers. The
ROV Status bit is cleared automatically when the buffer
register that caused the overflow is read by the CPU.
When a receive overflow occurs for a specific buffer
location, the old contents of the buffer are overwritten.
Note:
Note:
dsPIC30F5011/5013
TRANSMIT STATUS BITS
The transmit status bits only indicate
status for buffer locations that are used by
the module. If the buffer length is set to
less than four words, for example, the
unused buffer locations will not affect the
transmit status bits.
RECEIVE STATUS BITS
The receive status bits only indicate status
for buffer locations that are used by the
module. If the buffer length is set to less
than four words, for example, the unused
buffer locations will not affect the transmit
status bits.
DS70116H-page 125