Special considerations for HUADA MCU design

火辣西米秀

Special considerations for HUADA MCU design [Copy link]

 

	illustrate
1.Vcap pin	The core voltage output pin must be connected to ground with a 4.7uF capacitor and cannot be used for other functions or left floating. Note: If the customer wishes to use a smaller capacitor, the minimum capacitor for the L110/F003/F005 series is 4.7uF, and the minimum capacitor for the L13X/F03X series is 1uF.
2. About MODE pin (PD03 pin of L13X/F03X series)	1. During normal operation, PD03 must be connected to ground with a 10K resistor. After the MCU is powered on, the PD03 status is detected. When it is pulled low, it directly enters the user main program. When it is pulled high, it enters the Huada boot program (for UART port burning). Note: If PD03 is not pulled low when powered on, the user main program cannot be entered. 2. The L110/F003/F005 series does not have a MODE pin. By default, the Huada boot program is executed first after power-on. If no handshake signal from the offline burner is found, the user main program is automatically executed (it takes about 12mS from power-on to executing the user program). 3. When the SWD interface fails and cannot be connected, the UART port is required to re-burn the program. 4. The situations that cause the SWD port to fail are: a. The user main program enters deep sleep mode as soon as it is powered on and cannot be awakened; b. After burning the user program and encrypting it, the SWD cannot be connected the next time. 5. It is not recommended to use PD03 for other functions.
3. UART port for offline burning	The UART port used for offline programming is fixed on the MCU pins: L110/F003/F005 series corresponds to P35, P36; L13X/F03X series corresponds to PA09, PA10. Note: We have defined UART to the SWD pin in the new version of the bootloader, so that SWD and UART use the same programming port. If you have this requirement, please be sure to contact the agent (purchase the new version of the bootloader).
4. Get the ultimate ultra-low power consumption	In the L13X series, we have different models from 28pin to 64pin. For the 28pin/32pin/48pin models, the unpackaged pins should also be set to low output according to the 64pin. Otherwise, a certain percentage of chips will have high power consumption when in small batches. Similarly, the 16pin of L110 should also be set to the unpackaged pins according to the 20pin. You can ask our FAE for the relevant configuration code.
5. User programs should pay special attention to internal FLASH erasure	When the user program needs to erase or write the internal FLASH, the location of this user program must be within the 0-32K space.
6. Use the internal RC master clock RCH to switch frequency	When switching RCH, you must follow the process of gradually increasing 4M->8M->16M->22.12M/24M, or gradually reducing 22.12M/24M->16M->8M->4M. You cannot do it all at once. Or first switch to RCL as the system clock and then change RCH. For details, please refer to the user manual: System Clock Switching and related application notes.
5. User programs should pay special attention to internal FLASH erasure	When the user program needs to erase or write the internal FLASH, the location of this user program must be within the 0-32K space.
7.I/O port voltage cannot be greater than VCC	HuaDa L110/L13X/L17X/L19X/L07X, F003/F005/F030/F17X/F19X/F07X series I/O does not have 5V tolerant function, so the I/O voltage cannot be greater than VCC. When the I/O voltage is greater than VCC, the first feature that appears is ADC inaccuracy. Engineers like to use PC+USB-UART+serial port debugging assistant to view the data sent by UART during debugging. At this time, if the UART level is greater than the MCU power supply voltage VCC, the ADC data will be inaccurate.

秦天qintian0303

Is this an official recommendation or is it a summary of anomalies encountered during actual use?

elec921

Introduction to the typical system block diagram