Maxim Integrated MAX32665 User Manual

MAX32665-MAX32668 User Guide
Maxim Integrated Page 351 of 457
If a running pulse train engine is triggered by another pulse train’s Stop Event, Automatic Restart restarts the running pulse
train engine from the beginning of its pattern. If a pulse train engine is triggered by another pulse train’s Stop Event, and it
is not running, Automatic Restart sets the enable bit to 1, and starts the pulse train engine.
The settings for this mode are contained in the PTn_RESTART register for each pulse train engine. Note that the
configuration for automatic restart is set using the pulse engine(s) triggered by the automatic restart, not the pulse train
engine(s) that trigger the automatic restart. For example, the PT8_RESTART register configures which pulse train engine
triggers PT8 to restart.
Each pulse train engine can be configured to perform an Automatic Restart when it detects a Stop Event from one or two
pulse trains.
If PTn_RESTART.on_pt_n_loop_exit = 1, then pulse train engine n automatically restarts when it detects a Stop Event from
pulse train x, where x is the value in the 5-bit field PTn_RESTART.pt_n_select.
If PTn_RESTART.on_pt_y_loop_exit = 1, then pulse train engine n automatically restarts when it detects a Stop Event from
pulse train y, where y is the value in 5-bit field PTn_RESTART.pt_y_select.
A pulse train engine can be configured to restart on its own Stop Event, allowing the pulse train to run indefinitely.
Each individual pulse train can be configured for:
17.3.1.5 No Automatic Restart
Automatic Restart triggered by a stop event from pulse train x only
Automatic Restart triggered by a stop event from pulse train y only
Automatic Restart triggered by a stop event from both pulse train x and pulse train y
17.4 Enabling and Disabling a Pulse Train Output
The PTG_ENABLE register is used to enable and disable each of the individual pulse train outputs. Enable a given pulse train
output by setting the respective bit in the PTG_ENABLE register. Halt a pulse train output by clearing the respective bit in
the PTG_ENABLE register.
Note: Prior to changing a pulse train output’s configuration the corresponding pulse train output should be halted to prevent
unexpected behavior.
17.5 Atomic Pulse Train Output Enable and Disable
Deterministic enable and disable operations are critical for pulse train outputs that must be synchronized in an application.
The PTG_ENABLE register does not perform atomic access directly. Atomic operations are supported using the registers
PTG_SAFE_EN, PTG_SAFE_DIS.
For most pulse train peripherals, enabling and disabling individual pulse trains is performed by setting and clearing bits in
the global enable/disable register, which for this peripheral is PTG_ENABLE. For most Arm Cortex-M microcontrollers, this is
usually done by bit banding. Because bit banding performs a read, modify, write (RMW), some pulse trains could start and
end during the RMW operation, often with unpredictable results.
To ensure safe and predictable operation, two additional registers are used to enable and disable the outputs.
17.5.1 Pulse Train Atomic Enable
PTG_SAFE_EN “Global Safe Enable” is a write-only register. To safely enable outputs without a RMW, write a 32-bit value to
this register with a 1 in the bit positions corresponding to the pulse train engines to be enabled. This immediately sets to 1
the corresponding bits in the PTG_ENABLE register to 1, which enables the corresponding pulse train engine. Writing a 0 to
any bit position in the PTG_SAFE_EN register has no effect on the state of the corresponding pulse train enable bit. If the

Maxim Integrated MAX32665 Specifications

General

Brand	Maxim Integrated
Model	MAX32665
Category	Motherboard
Language	English