Hi NXP:
we're developing project with S32K312 and getting
I2C speed issue. I set Lpi2c parameters by reference manual and
getting correct speed 1Mbit/s by GUI(Lpi2c_setting.png),but I measured
I2C speed about clock waveform(LA_I2C_waveform.png) about 2.667Mhz.
Is it correct? thanks.
attachment:
I2C_setting_from_reference_manual.png
Lpi2c_setting.png
clock_ip_referencepoints.png
LA_I2C_waveform.png
current environment:
MCU:S32K312/100pin
S32DS Product:3.5.0.202207261815
RTD S32KXX:RTD5.0.0.202407261948
BR
Nelson
Yes, I'm afraid you shouldn't select LPI2C_FASTPLUS_MODE with 1 Mbit/s because the reference manual says so.
Hi Robin:
I modified I2C parameters from fast+ mode to fast mode in master mode,
and GUI show 400000(Baud rate), but I measured speed about 385Khz. it looks like
not accurate about GUI value and LA value, thanks.
attachment:
20250306-2-I2C_Test_S32K312.7z
BR
Nelson
Hi Robin:
just now, I saw reference manual as you posted information(LPI2C master mode operation supports up to fast Mode = 400KHz),
so S32K312 only supports fast mode in master mode(Up to 400Khz). if I want to adjust more than 400Khz, it is invaild for usage,
Is it correct? thanks.
BR
Nelson
Hi Robin:
I always use I2C master mode as LPI2C_FASTPLUS_MODE which support 1 Mbit/s.however,
I created simple project by GPIO and I2C function and set I2C parameters as current project,
and also tested I2C speed is about 888~914Khz on our PCB board. now you can change MCU package of attachment
from 100pin to 172pin for your EVB testing,thanks.
attachment:
20250306-I2C_Test_S32K312.7z
BR
Nelson
Sorry for the inconvenience.
It would be best if S32 Design Studio would warn you when you select master mode but exceed 400 kbps data rate.
S32K3XXRM mentioned:
•LPI2C slave mode operation supports up to high speed mode = 3.4MHz (3.4 Mbps data rate; effective data rate reduces according to I2C protocol).
•LPI2C master mode operation supports up to fast Mode = 400KHz (400 kbps data rate; effective data rate reduces according to I2C protocol).
Hi Robin:
I tried to change Clock_Ip_ReferencePoints from custom(8Mhz) to AIPS_SLOW_CLK(30Mhz),
and also changes I2C timing that it calculated I2C baud rate 1000000. but I measured waveform
about 864KHz. now I confuse about calculating result of Lpi2c GUI. please help us, thanks.
attachment:
clock_ip_referencepoints2.png
LA_I2C_waveform2.png
Lpi2c_setting2.png
BR
Nelson
Hi Nelson,
The LPI2C_CLK comes from AIPS_SLOW_CLK. So would you please configure AIPS_SLOW_CLK in clock_ip_referencepoints.png? Otherwise, the S32 Configuration Tool may use the wrong frequency (80MHz CUSTOM) for calculation.
Best Regards,
Robin
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