908E626_09 Datasheet, PDF (24/44 Pages) Freescale Semiconductor, Inc – Integrated Stepper Motor Driver with Embedded MCU and LIN Serial Communication

FUNCTIONAL DEVICE OPERATION
OPERATIONAL MODES
The LIN transmitter circuitry is enabled by setting the
PSON bit in the System Control Register (SYSCTL). If the
transmitter works in the current limitation region, the LINCL
bit in the System Status Register (SYSSTAT) is set. Due to
excessive power dissipation in the transmitter, software is
advised to monitor this bit and turn the transmitter off
immediately.
TXD Pin
The TXD pin is the MCU interface to control the state of the
LIN transmitter (see Figure , page 2). When TXD is LOW, LIN
output is low (dominant state). When TXD is HIGH, the LIN
output MOSFET is turned off. The TXD pin has an internal
pullup current source in order to set the LIN bus in recessive
state in the event, for instance, the microcontroller could not
control it during system power-up or power-down.
RXD Pin
The RXD transceiver pin is the MCU interface, which
reports the state of the LIN bus voltage. LIN HIGH (recessive
state) is reported by a high level on RXD, LIN LOW (dominant
state) by a low level on RXD.
STOP Mode/Wake-up Feature
During STOP mode operation the transmitter of the
physical layer is disabled. The receiver pin is still active and
able to detect wake-up events on the LIN bus line.If LIN
interrupt is enabled (LINIE bit in the Interrupt Mask Register
is set), a falling edge on the LIN line causes an interrupt. This
interrupt switches on the main voltage regulator and
generates a system wake-up.
Analog Multiplexer /ADOUT Pin
The ADOUT pin is the analog output interface to the ADC
of the MCU (see Figure , page 2). An analog multiplexer is
used to read six internal diagnostic analog voltages.
Current Recopy
The analog multiplexer is connected to the four low side
current sense circuits of the half-bridges. These sense
circuits offer a voltage proportional to the current through the
low side MOSFET. High or low resolution is selectable: 5.0V /
2.5A or 5.0V / 500mA, respectively. (Refer to Half-Bridge
Current Recopy on page 28.)
Temperature Sensor
The 908E626 includes an on-chip temperature sensor.
This sensor offers a voltage that is proportional to the actual
chip junction temperature.
V_SUP Prescaler
The V_SUP prescaler permits the reading or measurement
of the external supply voltage. The output of this voltage is
V_SUP / RATIO_VSUP.
The different internal diagnostic analog voltages can be
selected with the ADMUX Register.
Analog Multiplexer Configuration Register (ADMUX)
Register Name and Address: ADMUX - $07
Bit7 6
5
4
3
2
1 Bit0
Read 0
0
0
0
SS3 SS2 SS1 SS0
Write
Reset 0
0
0
0
0
0
0
0
SS3, SS2, SS1, and SS0 — A / D Input Select Bits
These read / write bits select the input to the ADC in the
microcontroller according to Table 7, page 24. Reset clears
SS3, SS2, SS1, and SS0 bits.
Table 7. Analog Multiplexer Configuration Register
SS3 SS2 SS1 SS0
Channel
0
0
0
0
Current Recopy HB1
0
0
0
1
Current Recopy HB2
0
0
1
0
Current Recopy HB3
0
0
1
1
Current Recopy HB4
0
1
0
0
V_SUP Prescaler
0
1
0
1
Temperature Sensor
0
1
1
0
0
1
1
1
1
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
Not Used
1
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
Power Output Register (POUT)
Register Name and Address: P_OUT - $0b
Bit7 6 5
4
3
2
1 Bit0
Read 0 0
0
0
0
0
HVDDO
0
Write
(16)
(16)
(16)
(16)
N
(16)
Reset 0 0 0
0
0
0
0
0
Notes
16. This bit must always be set to 0.
908E626
24
Analog Integrated Circuit Device Data
Freescale Semiconductor