
4/29/2020
Loongson 3A3000 / 3B3000 Processor User Manual
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13 Software and Hardware Design Guidelines
Loongson 3A3000 / 3B3000 processor pins downward compatible with Loongson 3A1000 processor, but the corresponding hardware and software needs
Make some configuration changes to enable the original compatibility mode, or open some new features of Godson 3A3000 / 3B3000,
This chapter focuses on the software and hardware settings of the Loongson 3A3000 / 3B3000 processor compared with Loongson 3A1000 / 2000
the difference.
13.1 Hardware modification guide
1. The original CORE_PLL_AVDD and DDR_PLL_AVDD (2.5v) are now 1.8v. If you use the original 3A1000 motherboard,
These two power supplies need to be changed from 2.5v to 1.8v. And these pins on 3A2000 / 3B2000 (including
HT0 / 1_PLL_AVDD) is NC, if you consider the compatibility with 3A2000 / 3B2000, these power supply voltages
Modified to 1.8v, or adopt 1.8v / 2.5v configurable design;
2. The original MC0 / 1_COMP_REF_RES is changed to NC pin. If the original 3A motherboard is used, no modification is required;
(Consistent with 3A2000)
3. The original HT0 / 1_PLL_REF is changed to NC pin. If you use the original 3A motherboard, you do n’t need to modify it; (with 3A2000
Consistent)
4. The original MC0 / 1_COMP_REF_GND is changed to MC0 / 1_A15. If you use the original 3A motherboard, you can
Modified; but if connected to a memory module, it can support a larger capacity memory; (same as 3A2000)