908E626 Datasheet, PDF (22/38 Pages) Freescale Semiconductor, Inc – Integrated Stepper Motor Driver with Embedded MCU and LIN Serial Communication

FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
TXD Terminal
The TXD terminal 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 terminal 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 Terminal
The RXD transceiver terminal 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.
Analog Multiplexer /ADOUT Terminal
The ADOUT terminal 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:
5.0 V / 2.5 A or 5.0 V / 500 mA, respectively. (Refer to Half-
Bridge Current Recopy on page 25.)
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 4, page 22. Reset clears
SS3, SS2, SS1, and SS0 bits.
Table 4. 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
(14)
(14)
(14)
(14)
N
(14)
Reset 0 0 0
0
0
0
0
0
Notes
14. This bit must always be set to 0.
HVDDON — HVDD On Bit
This read/write bit enables HVDD output. Reset clears the
HVDDON bit.
• 1 = HVDD enabled.
• 0 = HVDD disabled.
HALF-BRIDGES
Outputs HB1 : HB4 provide four low-resistive half-bridge
output stages. The half-bridges can be used in H-Bridge,
high-side, or low-side configurations.
Reset clears all bits in the H-Bridge Output Register
(HBOUT) owing to the fact that all half-bridge outputs are
switched off.
HB1: HB4 output features:
• Short circuit (overcurrent) protection on high-side and
low-side MOSFETs.
• Current recopy feature (low side MOSFET).
908E626
22
Analog Integrated Circuit Device Data
Freescale Semiconductor