山东省电子设计竞赛题目 多功能电子计价器（包括选择商品（在eeprom里），称量重量，显示，并保存记录具有断电保护功能）-Shandong Province Electronic Design Contest topic multifunctional electronic meter (including the selection of goods (in eeprom inside), weigh, display, and record-keeping with power protec