MC33580 Datasheet, PDF (24/38 Pages) Freescale Semiconductor, Inc – Quad High-Side Switch (Quad 15 mΩ)

FUNCTIONAL DEVICE OPERATION
LOGIC COMMANDS AND REGISTERS
Bits D1 : D0 (OCLT1_s : OCLT0_s) allow the MCU to select
one of three overcurrent fault blanking times defined in
Table 13. Note that these time-outs apply only to the
overcurrent low detection levels. If the selected overcurrent
high level is reached, the device will latch off within 20 µs.
Table 13. Overcurrent Low Detection Blanking Time
OCLT[1:0]_s*
Timing
00
155 ms
01
Do not use
10
75 ms
11
150 µs
* “_s” refers to the output, which is selected through bits D12 : D11.
A logic [1] on bit D2 (OCL_DIS_s) disables the overcurrent
low detection feature. When disabled, there is no timeout for
the selected output and the overcurrent low detection feature
is disabled.
A logic [1] on bit D3 (OL_DIS_s) disables the open load
(OL) detection feature for the output corresponding to the
state of bits D12 : D11.
ADDRESS A₁A₀100 — DIRECT INPUT CONTROL
REGISTER (DICR)
The DICR register is used by the MCU to enable, disable,
or configure the direct IN pin control of each output. Each
output is independently selected for configuration based on
the state bits D12 : D11 (refer to Table 10, page 23).
For the selected output, a logic [0] on bit D1 (DIR_DIS_s)
will enable the output for direct control. A logic [1] on bit D1
will disable the output from direct control.
While addressing this register, if the Input was enabled for
direct control, a logic [1] for the D0 (A/O_s) bit will result in a
Boolean AND of the IN pin with its corresponding IN_SPI
D[4:0] message bit when addressing OCR0. Similarly, a logic
[0] on the D0 pin results in a Boolean OR of the IN pin to the
corresponding message bits when addressing the OCR0.
This register is especially useful if several loads are required
to be independently PWM controlled. For example, the IN
pins of several devices can be configured to operate all of the
outputs with one PWM output from the MCU. If each output
is then configured to be Boolean ANDed to its respective IN
pin, each output can be individually turned OFF by SPI while
controlling all of the outputs, commanded on with the single
PWM output.
A logic [1] on bit D2 (CSNS_high_s) is used to select the
high ratio on the CSNS pin for the selected output. The
default value [0] is used to select the low ratio (Table 14).
Table 14. Current Sense Ratio
CSNS_high_s* (D2)
Current Sense Ratio
HS0 to HS3
0
1/13000
1
1/38000
* “_s” refers to the output, which is selected through bits D12 : D11;
refer to Table 10, page 23.
A logic [1] on bit D3 (FAST_SR_s) is used to select the
high speed slew rate for the selected output, the default value
[0] corresponds to the low speed slew rate.
ADDRESS 00101 — UNDERVOLTAGE /
OVERVOLTAGE AND HS[0,1]
OVERTEMPERATURE REGISTER (UOVR)
The UOVR register disables the undervoltage (D1) and/or
overvoltage (D0) protection. When these two bits are [0], the
under- and overvoltage are active (default value).
The UOVR register allows the overtemperature detection
latching on the HS0 and HS1. To latch the overtemperature,
the bits (OT_latch_1 and OT_latch_0) must be set to [0]
which is the default value. To disable the latching, both bits
must be set to [1].
ADDRESS 01101 — WATCHDOG AND HS[2,3]
OVERTEMPERATURE REGISTER (WDR)
The WDR register is used by the MCU to configure the
Watchdog timeout. The Watchdog timeout is configured
using bits D1 and D0. When D1 and D0 bits are programmed
for the desired watchdog timeout period (Table 15), the
WDSPI bit should be toggled as well, ensuring the new
timeout period is programmed at the beginning of a new
count sequence.
The WDR register allows the overtemperature detection
latching on the HS2 and HS3. To latch the overtemperature,
the bits (OT_latch_3 and OT_latch_2) must be set to [0]
which is the default value. To disable the latching, both bits
must be set to [1].
Table 15. Watchdog Timeout
WD[1:0] (D1, D0)
00
01
10
11
Timing (ms)
558
279
2250
1125
33580
24
Analog Integrated Circuit Device Data
Freescale Semiconductor