This document introduces the mikroBUS compatible click boards for Ambiq Micro's ultra low power real time clock (RTC) devices.
For more information of mikroBUS, please visit https://www.mikroe.com/mikrobus.
For more information of AM18x5 series RTC, please visit the following links:
Product introduction page: https://ambiqmicro.com/rtc/
AM18x5 datasheet: https://ambiqmicro.com/static/rtc/files/AM18X5_Data_Sheet_DS0003V1p3.pdf
AMx8x5 silicon errata: https://ambiqmicro.com/static/rtc/files/errata_sheet_er0006v1p0_FxAvP0Y.pdf
AMx8x5 power management: https://ambiqmicro.com/static/rtc/files/AM18X5_Power_Management_App_Note_AN0001V0p04.pdf
AMx8x5 Autocalibiration App Note: https://ambiqmicro.com/static/rtc/files/AMX8X5-Autocalibration-App-Note-AN0002V0p03_WFbDzdL.pdf
AMx8x5 Startup Timing App Note: https://ambiqmicro.com/static/rtc/files/AMX8XX-Startup-Timing-App-Note-AN0004V0p02_6JnlmDb.pdf
AMx8x5 Counter Loss App Note: https://ambiqmicro.com/static/rtc/files/AMX8XX-Counter-Loss-App-Note-AN0005V1p0_FJrcdY7.pdf
AMx8x5 Reset VCC Transient Behavior: https://ambiqmicro.com/static/rtc/files/AMX8XX_Reset_VCC_Transient_Behavior_AN0006V0p02_HRbEYEG.pdf
AMx8x5 Capacitor Backup Power: https://ambiqmicro.com/static/rtc/files/AMX8X5_Capacitor_Backup_Power_AN0007V0p03_XWFbHmW.pdf
AMx8x5 Hardware Design App Note: https://ambiqmicro.com/static/rtc/files/AMX8XX-Hardware-Design-App-Note-AN0008V0p04_4pDDhZX.pdf
Getting Started with AM18x5 RTC mikroBUS click boards
The AM18x5 RTC mikroBUS click boards (referred to as RTC EVBs in text below), works with any mikroBUS compatible socket.
With Ambiq Micro's MCU evaluation board (EVB), it requires the mikroBUS shield to convert the connection from the MCU EVB into mikroBUS connectors.
(For information about the mikroBUS shield board, please contact firstname.lastname@example.org)
Currently, we have prepared 2 different RTC EVBs: the AM1805 EVB (I2C interface) and AM1815 EVB (SPI interface).
Both RTC EVBs can be placed in any of the 3 mikroBUS sockets.
(In our example program, we are using socket 1.)
Once you set up the hardware, connect the board stack to PC with USB cable.
You can try the following pre-compiled binaries first to confirm the function of the boards:
Download binary with Segger J-Link Flash lite:
Both examples works on Apollo2Blue EVB.
The examples will setup target RTC device on the EVB from Apollo2Blue MCU with an interrupt from AM18x5 at 500ms interval.
Every time when interrupt happens, the MCU will read out the current time from the RTC and print it out from SWO channel.
Both examples set time to 6th August 2012, 5:17 UTC. (NASA's Curiosity Mars rover landing time.)
Monitor SWO print with Segger J-Link SWO Viewer:
Set SWOClock to 1000kHz.
Once connected, press reset button on the Apollo2Blue EVB.
The example binaries also enables the CLKOUT on the RTC.
You can probe the RTC CKO test point (TP2) with a frequency counter to check the CLKOUT signal.
In this case, the crystal is roughly -58ppm.
Source code of the examples:
Example projects are located in:
The example projects comes with IAR project only, please use IAR Embedded workbench 8.32.2 or later.
Hardware Information of AM1805 RTC EVB:
Hardware Information of AM1815 RTC EVB:
(For design source files, please contact Ambiq Micro)