Datasheet
POWER-UP AND POWER-DOWN SEQUENCES
Power UP Sequence:
1.
Turn ON VIO (pin 19) & Hold RST (pin 8) HIGH
2.
Turn ON VDDA (pin 15) and VDDC (pin 6)
3.
Release RST (pin 8) back to LOW
4.
Set PLLE (bit 10 of register 1Ah) to LOW
5.
Set PLLE (bit 10 of register 1Ah) to HIGH
Power DOWN Sequence:
1.
Insure VIO (pin 19) always greater than VDDA (pin 15)
& VDDC (pin 6)
FIRING SEQUENCE EXAMPLES
Example 1A (Code Excitation)
In Example 1A, a 64-bit pulse pattern is used for code excitation with the following parameters:
•
Each of the eight channels have the same 64-bit pulse pattern with respect to the P part of the pattern (default 64-bit hex value
= 5555 5555 5555 5555) and the N part of the pattern (default 64-bit hex value = AAAA AAAA AAAA AAAA).
•
The output pulse pulse width is 100ns, 5MHz for one-on-one-off pattern.
•
The delay between adjacent Channels is approximately 13.28 ns (i.e, two coarse delays with a delay step of 6.25 ns and one
fine delay with a delay step of 0.78 ns). Channel 0 has no delay.
•
The Pulse Width Adjust feature for all channels are disabled.
STEP 1
•
Write to Register 1Ah to configure the pulse pattern length, pulse output frequency, and enable PLL. Based on the Register
Definition in Table 4, here Register 1Ah (14-bit Binary) = 0001 001 0000 111 b
RESERVED 0 reserved bit is kept at “0”
CW 0 beamformer is NOT in the CW firing mode
INV_FIRE_EN 0 beamformer is NOT in the “invert firing” mode
PLL_EN 1 PLL is enabled
FREQ_DIV 001 0000
pulse width is one period of 1/16 of the master clock frequency
(160MHz / 16 = 10MHz, i.e. 100ns period)
PAT_LEN 111 pulse pattern length is 64 bits.
•
RESERVED (1-bit Binary) = “0” – reserved bit is kept at “0”.
•
CW (1-bit Binary) = “0” – beamformer is not in the CW firing mode
•
INV_FIRE_EN (1-bit Binary) = “0” – beamformer is NOT in the “invert firing” mode
•
PLL_EN (1-bit Binary) = “1” – PLL is enabled.
•
FREQ_DIV (7-bit Binary) = “001 0000” – 1/16 of the master clock (160MHz) for 100ns pulse width.
•
PAT_LEN (3-bit Binary) = “111” – pulse pattern length is 64 bit.
30129709
FIGURE 14. Write Register 1Ah with 14 bit = 0001 0010000 111
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LM96570