Analog Integrated Circuit Device Data
Freescale Semiconductor
23
33976
FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
command after re-enabling the gauge using the PECCR
command. This bit remains logic [1] until the gauge is
enabled.
0 = Temperature within range
1 = Gauge 1 maximum allowable junction temperature
condition has been reached
OT0 (OD0) — Gauge 0 Junction Overtemperature. A
logic [1] on this bit indicates that the coil drive circuitry
dedicated to drive Gauge 0 has exceeded the maximum
allowable junction temperature since the last SPI
communication and that Gauge 0 has been disabled. It is
recommended that the pointer be re-calibrated using the RTZ
command after re-enabling the gauge using the PECCR
command. This bit remains logic [1] until the gauge is re-
enabled.
0 = Temperature within range1 = Gauge 0 maximum
allowable junction temperature condition is reached
RTZ Accumulator Status Information
Most recent valid PECCR command resulting in the RTZ
Accumulator status output:
The bits in
Table 22
are
read-only
bits.
RTZ (OD15) — RTZ Bit Is Enabled or Disabled. A logic [1]
on this bit indicates that the Gauge is in the process of
returning to the zero position as requested with the RTZ
command. This bit will continue to indicate a logic [1] until the
SPI message following a detection of the zero position, or the
RTZ feature is commanded OFF using the RTZ message.
0 = Return to Zero disabled
1 = Return to Zero enabled successfully
ACC14:ACC0 (OD14:OD0) — These 15 bits are from the
RTZ accumulator. They represent the integrated signal
present on the non-driven coil during an RTZ event. These
bits are logic [0] after power-on reset, or after the
RST
pin
transitions from logic [0] to [1]. After an RTZ event, they will
represent the last RTZ accumulator result before the RTZ
was stopped. ACC14 is the MSB and is the sign bit used for
zero detection. Negative numbers have MSB logic [1] and
are coded in two’s complement.
Figure 8. RTZ Accumulator (Typical)
The analog-to-digital converter's linear input range covers
the expected magnitude of motor back e.m.f. signals, which
is usually less than 500mV. Input signals greater than this will
not cause any damage (the circuit is connected to the motor
H-Bridge drivers, and thus is exposed to the full magnitude of
the drive voltages), but may cause some small loss of
linearity. A typical plot of output vs. input is shown in
Figure 8
for 4ms step times.
Gauge 0 Pointer Position Status Information
Most recent valid PECCR command resulting in the
Gauge 0 Pointer Position status output:
Table 21.
D11
D10
D9
D8
1
0
x
x
x = Don’t care.
Table 22. RTZ Accumulator Status Output Register
Bits
OD15
OD14
OD13
OD12
OD11
OD10
OD9
OD8
OD7
OD6
OD5
OD4
OD3
OD2
OD1
OD0
Read
RTZ
ACC14 ACC13 ACC12 ACC11 ACC10 ACC9
ACC8
ACC7
ACC6
ACC5
ACC4
ACC3
AC2C
ACC1
ACC0
Write
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
Table 23.
D11
D10
D9
D8
1
1
0
0