Скорей всего, это эффект защелкивания (latch-up), ЕМНИП. Последовательность подачи питания значения не имеет:
MAX II devices are designed to operate in multiple-voltage environments where it may be difficult to control power sequencing. Therefore, MAX II devices are designed to tolerate any possible power-up sequence. Either VCCINT or VCCIO can initially supply power to the device, and 3.3-V, 2.5-V, 1.8-V, or 1.5-V input signals can drive the devices without special precautions before VCCINT or VCCIO is applied.
Power-Up ProblemsExcessive voltage or current on I/O pins during power-up can cause one of the devices in the JTAG chain to experience latch-up. Check if any of the devices are hot to the touch; hot devices have probably experienced latch-up and may have been damaged. In this situation, check all voltage sources to make sure that excessive voltage or current is not being fed into the device. Then, replace the affected device and try programming again.
См. стр 205.
Хаос (07.04.2018 14:02, просмотров: 1) ответил Meteor на Берем пункт 2, EPM1270 питание портов B1 и B2 от 2,5В; питание B3 и B4 от 3,3В. Есть выбор запитки ядра либо от 2,5В, либо от 3,3В. Включаю питание от 2,5В.