MCP25055T-I/SL Microchip Technology, MCP25055T-I/SL Datasheet - Page 27

• Manufacturer Part Number: MCP25055T-I/SL
• Description: IC I/O EXPANDER CAN 8B 14SOIC
• Manufacturer: Microchip Technology

Specifications of MCP25055T-I/SL

• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Interface: 1-Wire, CAN
• Number Of I /o: 8
• Interrupt Output: No
• Frequency - Clock: 4MHz
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Includes: ADC, Memory, PWM
• Product: Controller Area Network (CAN)
• Number Of Transceivers: 1
• Data Rate: 1 Mbps
• Supply Voltage (max): 5.5 V
• Supply Voltage (min): 2.7 V
• Supply Current (max): 20 mA
• Maximum Operating Temperature: + 150 C
• Minimum Operating Temperature: - 65 C
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: MCP25055TI/SL

4.5
The MCP2502X/5X can automatically initiate four
different message types to indicate the following
situations:
• Edge detected on a digital input (TXID2).
• Threshold exceeded on an analog input (TXID2).
• Error condition (Read Error output message).
• Scheduled transmissions (TXID0).
The buffers have an implied transmit priority, where
buffer 2 is the highest and buffer 0 is the lowest.
Therefore, multiple message buffers can be requested
for transmission and each one will be sent in order of
priority.
4.5.1
Each GPIO pin configured as a digital input can be
individually configured to automatically transmit a
message when a defined edge occurs, as explained in
the GPIO module section. When transmitting this
message, the MCP2502X/5X uses TXID2. The DLC is
set to two and the first two bytes of the Read A/D
registers (IOINTFL and GPIO) are sent.
4.5.2
Each GPIO pin that has been configured as an analog
input can be individually configured to automatically
transmit a message when a threshold is exceeded as
described in the Analog-to-Digital Converter Module
section. The MCP2502X/5X sends TXID2 when
transmitting this message. The DLC is set to eight and
the eight bytes of the ‘Read A/D Registers’ are sent.
4.5.2.1
This function is automatic and will insure that an analog
value that is on the compare edge (i.e., toggling LSb)
does not fill the CAN bus with continuous A/D message
transmissions.
The hysteresis uses the two LSb’s of the compare
register. These two bits are forced and are not
configurable by the user. They will be forced to either
b’00’ or b’11’, depending on the compare polarity. If
configured for A/D result > compare register, the
automatic transmission will occur when the A/D value
is greater than or equal to b’nnnn nnnn 11’ and
reset when less than or equal to b’nnnn nnnn 00’.
The opposite conditions must occur if the compare
polarity is set for A/D result < compare register.
© 2007 Microchip Technology Inc.
Note:
Automatic Transmission
The GPIO register that is sent with the
message (data byte 2) can be ignored if
there are no digital inputs enabled for
change-of-state, as it contains no useful
information for the Analog Input Threshold
Detect function.
DIGITAL INPUT EDGE DETECTION
ANALOG INPUT THRESHOLD
DETECTION
Hysteresis Function
A hysteresis example:
• The user sets the upper-eight bits of the 10-bit
• The user sets the polarity of the compare
• When the A/D conversion exceeds the compare
• In order for the automatic transmission to occur
FIGURE 4-1:
4.5.3
The MCP2502X/5X can be configured to automatically
transmit a message whenever one or more of the
following error conditions occur:
• Receiver has entered error-warning state
• Receiver has entered error-passive state
• Transmitter has entered error-warning state
• Transmitter has entered error-passive state
• A Receive buffer has overflowed
LSbs = b’11’
LSbs = b’00’
LSbs = b’00’
LSbs = b’11’
compare register (ADCMP0H). The lower-two bits
of the compare register are not configurable by
the user and are forced to either b’11’ or b’00’
depending on the polarity of the compare
threshold (i.e., transmit is triggered above or
below the compare value via the IOINTPO
register).
threshold (IOINTPO). In this example, the
threshold is set for triggering a message on an
A/D > compare register. The two LSb’s are forced
to b’11’.
register (b’nnnn nnnn 11’), an automatic
transmission will occur once.
again, the A/D value must first drop below the
compare register b’nnnn nnnn 00’ and then
back above the compare register
b’nnnn nnnn 11’.
Set to Trigger when A/D<Compare Register
Set to Trigger when A/D>Compare Register
A/D above compare,
Message sent
ERROR CONDITION
A/D below compare,
Message sent
MCP2502X/5X
A/D below compare,
HYSTERESIS
FUNCTION
Reset
A/D above compare,
A/D above compare,
Message sent
Reset
A/D below compare,
DS21664D-page 27
Message sent