Difference between revisions of "FPGA Clock/Trigger generator"
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| − | * DLL1: CLKIN=32MHz -> *25, / |
+ | * DLL1: CLKIN=32MHz -> *25, /8 -> 100MHz |
* DLL2: CLKIN=100Mhz -> *5, /7 -> 71.428MHz |
* DLL2: CLKIN=100Mhz -> *5, /7 -> 71.428MHz |
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* DLL3: CLKIN=71.428MHz/2 |
* DLL3: CLKIN=71.428MHz/2 |
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* DLL4: CLKIN=142.86MHz |
* DLL4: CLKIN=142.86MHz |
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| + | converting frequencies using [[DCM module VHDL code]] |
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| − | |||
<nowiki> |
<nowiki> |
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MR <=MR1 xor MR2 |
MR <=MR1 xor MR2 |
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| Line 16: | Line 16: | ||
</nowiki> |
</nowiki> |
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=differential signals= |
=differential signals= |
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| + | ==Measurements== |
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| ⚫ | |||
| + | When defining an output as LVDS_25 (VCCO jumper to 3.3V): |
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| + | * Voltage over + and - pair: 0.559 / -0.558 V |
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| + | * Current (when shorted): 10.69/-10.62 mA |
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| + | * Voltage over GND and + (or -): 1.53 / 0.97V |
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| + | |||
| + | VCCO Jumper to 2.5V: |
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| + | * Voltage over + and - pair: 0.567 / -0.565 V |
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| + | * Current (when shorted): 10.71 / -10.64 mA |
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| + | * Voltage over GND and + (or -): 1.53 / 0.97V |
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| + | |||
| + | VCCO Jumper to 1.2V: |
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| + | * Voltage over + and - pair: ? / -0.5228 V |
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| + | * Current (when shorted): ? / 4.59 mA |
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| + | * Voltage over GND and + / - : 0.27 / 0.79 V |
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| + | |||
| + | ==Available Lines== |
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| + | As I'm using (4 pins on) the right-side for the DX Display TM1638 connection, I try to only use the left side; some of the available differential pins are: |
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| + | *C2/C3 = P94/P95 = IO_L06 (P94 connected to single-signal) |
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| + | *C5/C6 = P2/P3 = IO_L01 |
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| + | *C7/C8 = P4/P5 = IO_L02 |
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| + | *C9/C10 = P9/P10 = IO_L03 (P9/P10 connected to differential) |
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| + | |||
| + | ==Xilinx code to drive Differential signals== |
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| ⚫ | |||
<nowiki>NET test_sig_out_n LOC = "P12"; # C12 |
<nowiki>NET test_sig_out_n LOC = "P12"; # C12 |
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| Line 25: | Line 49: | ||
Then, to drive/read the differential signals, use in VHDL: |
Then, to drive/read the differential signals, use in VHDL: |
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| − | <nowiki> |
+ | <nowiki> |
| + | |||
| + | |||
| + | library UNISIM; |
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| + | use UNISIM.VComponents.all; |
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| + | -- |
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| + | -- |
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| + | output_buffer: OBUFDS |
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generic map ( IOSTANDARD => "LVDS_25") |
generic map ( IOSTANDARD => "LVDS_25") |
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port map ( |
port map ( |
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Latest revision as of 00:27, 28 May 2013
- DLL1: CLKIN=32MHz -> *25, /8 -> 100MHz
- DLL2: CLKIN=100Mhz -> *5, /7 -> 71.428MHz
- DLL3: CLKIN=71.428MHz/2
- DLL4: CLKIN=142.86MHz
converting frequencies using DCM module VHDL code
MR <=MR1 xor MR2
MR1<=CLKIN3
MR2<=CLKIN3, variable phase delayed
CCR <=
if rising_edge(CLKIN4) then
CCR<=trigger xor CCRCLK;
CCRCLK<=not CCRCLK;
fi
differential signals
Measurements
When defining an output as LVDS_25 (VCCO jumper to 3.3V):
- Voltage over + and - pair: 0.559 / -0.558 V
- Current (when shorted): 10.69/-10.62 mA
- Voltage over GND and + (or -): 1.53 / 0.97V
VCCO Jumper to 2.5V:
- Voltage over + and - pair: 0.567 / -0.565 V
- Current (when shorted): 10.71 / -10.64 mA
- Voltage over GND and + (or -): 1.53 / 0.97V
VCCO Jumper to 1.2V:
- Voltage over + and - pair: ? / -0.5228 V
- Current (when shorted): ? / 4.59 mA
- Voltage over GND and + / - : 0.27 / 0.79 V
Available Lines
As I'm using (4 pins on) the right-side for the DX Display TM1638 connection, I try to only use the left side; some of the available differential pins are:
- C2/C3 = P94/P95 = IO_L06 (P94 connected to single-signal)
- C5/C6 = P2/P3 = IO_L01
- C7/C8 = P4/P5 = IO_L02
- C9/C10 = P9/P10 = IO_L03 (P9/P10 connected to differential)
Xilinx code to drive Differential signals
information copied from Hamster Code
NET test_sig_out_n LOC = "P12"; # C12 NET test_sig_out_p LOC = "P11"; # C11 NET test_sig_in_p LOC = "P15"; # C13 NET test_sig_in_n LOC = "P16"; # C14
Then, to drive/read the differential signals, use in VHDL:
library UNISIM;
use UNISIM.VComponents.all;
--
--
output_buffer: OBUFDS
generic map ( IOSTANDARD => "LVDS_25")
port map (
O => test_sig_out_p,
OB => test_sig_out_n,
I => test_sig_out
);
input_buffer : IBUFDS
generic map (
DIFF_TERM => TRUE,
IBUF_DELAY_VALUE => "0",
IFD_DELAY_VALUE => "AUTO",
IOSTANDARD => "LVDS_25")
port map (
O => test_sig_in, -- Buffer output
I => test_sig_in_p, -- Diff_p buffer input (connect directly to top-level port)
IB => test_sig_in_n -- Diff_n buffer input (connect directly to top-level port)
);
