Datasheet

MCP2003/4/3A/4A
DS20002230E-page 4  2010-2013 Microchip Technology Inc.
1.3 Modes of Operation
For an overview of all operational modes, refer to
Table 1-1.
1.3.1 POWER-DOWN MODE
In Power-Down mode, everything is off except the
wake-up section. This is the lowest power mode. The
receiver is off, thus its output is open-drain.
On CS going to a high level or a falling edge on WAKE
(MCP2003/MCP2003A only), the device will enter
Ready mode as soon as internal voltage stabilizes.
Refer to the AC Spec table. In addition, LIN bus
activity will change the device from Power-down mode
to ready mode; MCP2003/4 wakes-up on a falling
edge on L
BUS, followed by a low level lasting at least
20 µs. MCP2003A/4A wakes-up on a rising edge on
LBUS, followed by a high level lasting 70 µs typically.
Refer to Figure 1-2 — Figure 1-5 about remote wake
up. If CS is held high as the device transitions from
Power-Down to Ready mode, the device will transition
to either Operation or Transmitter Off mode,
depending on T
XD input, as soon as internal voltages
stabilize.
1.3.2 READY MODE
Upon entering the Ready mode, VREN is enabled and
the receiver detect circuit is powered up. The transmit-
ter remains disabled and the device is ready to receive
data but not to transmit.
Upon V
BB supply pin power-on, the device will remain
in Ready mode as long as CS is low. When CS transi-
tions high, the device will either enter Operation mode,
if T
XD pin is held high, or the device will enter Transmit-
ter Off mode, if T
XD pin is held low.
1.3.3 OPERATION MODE
In this mode, all internal modules are operational.
The device will go into Power-Down mode on the falling
edge of CS. For the MCP2003/4 device, a specific
process should be followed to put all nodes into Power-
Down mode. Refer to Section 1.6 “MCP2003/4 and
MCP2003A/4A Difference Details” and Figure 1-6.
The device will enter Transmitter Off mode in the event
of a Fault condition. These include: thermal overload,
bus contention and T
XD timer expiration.
The MCP2004/2004A device can also enter
Transmitter Off mode if the FAULT
/TXE pin is pulled
low. The V
BB to LBUS pull-up resistor is connected only
in Operation mode.
1.3.4 TRANSMITTER OFF MODE
Transmitter Off mode is reached whenever the
transmitter is disabled either due to a Fault condition or
pulling the FAULT/TXE pin low on the MCP2004/
2004A. The fault conditions include: thermal overload,
bus contention, RXD monitoring or TXD timer expiration.
The device will go into Power-Down mode on the falling
edge of CS, or return to Operation mode if all faults are
resolved and the FAULT
/TXE pin on the MCP2004/
2004A is high.
FIGURE 1-2: OPERATIONAL MODES STATE DIAGRAM – MCP2003
POR
VREN OFF
RX OFF
TX OFF
VBAT>5.5V
Ready
VREN ON
RX ON
TX OFF
TOFF
Mode
VREN ON
RX ON
TX OFF
Operation
Mode
VREN ON
RX ON
TX ON
POWER
DOWN
VREN OFF
RX OFF
TX OFF
CS=1 & TXD=0
CS=1 & TXD=1
CS=1 & TXD=1 & No Fault
Fault (thermal or timer)
CS=0
Falling edge on LIN
or CS=1
or falling edge on WAKE PIN
CS=0