MioLink revisions comparsion
There are currently 2 hardware revisions of the MioLink board (rev.A and rev.B), this page describes their differences.
Note: The information on this page applies only to MioLink and is not relevant to MioLink_Pico.
In rev.A, there is a hardware bug that causes the current value provided by the device on pin 1 (Vtref) of the debug connector to be unlimited, as pin 5 of the TPS2553 is mistakenly connected to ground (pin 2) instead of the input voltage (pin 1).
As a result, the current is limited only by the LDO (LP5907MFX-3.3), which means approximately 250mA of total current on the 3.3V line.
This problem was fixed and rev.B.
Also rev.B uses a DC-DC converter to get 3.3V from 5V, and the current supplied to the debug connector is limited to around ~350 mA (min. 300, max. 400).
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In rev. A, the TMS_DIR and TCK pins are not consecutive, which prevents changing the value of the TMS_DIR pin using side-set.
Instead, an additional set pins command is required.
In rev. B, this has been fixed. The side-set pins are now TCK and TMS_DIR, allowing the TMS direction to be changed and the direction of the external level shifter to be switched with a single PIO command (set pindirs, x side y) instead of the two commands required in rev. A (set pindirs, x and set pins, y).
| rev. A | rev. B |
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In rev. A, the order of the LEDs (from left to right) is as follows: PWR, ACT, SER, ERR, which does not match the standard order in the Blackmagic Probe (PWR, ERR, ACT, SER).
Therefore, in rev. B, the LED order was changed to match the order in the Blackmagic Probe.
| rev. A | rev. B |
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rev. A devices have two buttons: BOOT and RST.
In rev. B, the RST button was removed, as USB-MSC boot mode can be triggered by holding the BOOT button while the device is powered off, then powering it on (i.e., plugging in the USB cable).