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EP1C20F400I7ES 数据表(PDF) 41 Page - Altera Corporation |
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EP1C20F400I7ES 数据表(HTML) 41 Page - Altera Corporation |
41 / 106 page Altera Corporation 2–35 May 2008 Preliminary Global Clock Network and Phase-Locked Loops Clock Multiplication and Division Cyclone PLLs provide clock synthesis for PLL output ports using m/(n × post scale counter) scaling factors. The input clock is divided by a pre-scale divider, n, and is then multiplied by the m feedback factor. The control loop drives the VCO to match fIN × (m/n). Each output port has a unique post-scale counter to divide down the high-frequency VCO. For multiple PLL outputs with different frequencies, the VCO is set to the least-common multiple of the output frequencies that meets its frequency specifications. Then, the post-scale dividers scale down the output frequency for each output port. For example, if the output frequencies required from one PLL are 33 and 66 MHz, the VCO is set to 330 MHz (the least-common multiple in the VCO's range). Each PLL has one pre-scale divider, n, that can range in value from 1 to 32. Each PLL also has one multiply divider, m, that can range in value from 2 to 32. Global clock outputs have two post scale G dividers for global clock outputs, and external clock outputs have an E divider for external clock output, both ranging from 1 to 32. The Quartus II software automatically chooses the appropriate scaling factors according to the input frequency, multiplication, and division values entered. Dual-Purpose Clock Pins DPCLK0 (3) ——— v ———— DPCLK1 (3) —— v ————— DPCLK2 v ——————— DPCLK3 ———— v ——— DPCLK4 —————— v — DPCLK5 (3) ——————— v DPCLK6 ————— v —— DPCLK7 — v —————— Notes to Table 2–7: (1) EP1C3 devices only have one PLL (PLL 1). (2) EP1C3 devices in the 100-pin TQFP package do not have dedicated clock pins CLK1 and CLK3. (3) EP1C3 devices in the 100-pin TQFP package do not have the DPCLK0, DPCLK1, or DPCLK5 pins. Table 2–7. Global Clock Network Sources (Part 2 of 2) Source GCLK0 GCLK1 GCLK2 GCLK3 GCLK4 GCLK5 GCLK6 GCLK7 |
类似零件编号 - EP1C20F400I7ES |
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类似说明 - EP1C20F400I7ES |
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