BB5 Series MCU: Features, Applications and Comparison

Today I'm going to show you a new 8-bit MCU from Silicon Labs called the BB5 series, which is a low-cost MCU. Microchip Semiconductor's STC series, STMicroelectronics' STM8 series, and a few more local brands are the most prevalent 8-bit MCUs. You may be unfamiliar with SiliconLabs' 8-bit MCU. Let's take a closer look at the BB5 series.

Ⅰ. Architecture and Features of BB5 Series

BB5 Series Architecture

First, check-in the upper left corner at the core and memory. Although the BB5 series retains the basic 8051 core, its system clock may reach 50MHz, which is a pretty high frequency for an 8-bit MCU. The BB5 series' flash and RAM memory are both quite substantial; the flash memory may go up to 32kB, and the RAM memory is roughly 2kB. It has a two-wire debug interface that makes downloading, debugging, and emulating the chip's program a breeze.

Then there's time management. We must concentrate on the clock. The BB5 series includes a 50MHz internal clock crystal oscillator with a 2 percent crystal oscillator inaccuracy, which is extremely accurate.

The BB5 series provides a wide voltage range of 1.8-5.5V in terms of power supply and energy consumption. The BB5 series, despite having a high primary frequency, also has an excellent performance in terms of low power consumption, with a power consumption of 10A. The wake-up speed is likewise quite rapid in low power consumption mode, 30 seconds.

The BB5 series' encryption is accomplished using a 6-bit CRC and an 8-bit SFR bus.

Take a peek at the BB5 series' external devices. There are two UART serial ports, one SPI port, up to two I2C ports, and up to 29 GPIO ports. In terms of timers, the BB5 series includes a dedicated watchdog timer that can generate 6 PWM waves, as well as a 16-bit timer.

Last but not least, have a look at the analog module. It's a lot nicer here. 12-bit ADCs are supported by the BB5 series. They are usually 10-bit ADCs in 8-bit MCUs. There aren't many 12-bit ADCs on the market. The other difference is that most 8-bit MCUs lack DACs, whereas the BB5 series does. It has a 10bit DAC and can be used as an analog output.

BB5 Features summary：

●The BB5 series is a 90nm package based on the previous generation BB3's 180nm technology.

●It has a 50MHz optimized 8051 core, which makes it quicker than similar models.

●RAM 0.5-2kB, flash 4-32kB.

●According to package specifications, the number of GPIOs can range from 8 to 29 general-purpose I/Os.

●Excellent ability to simulate. The 12-bit ADC is quite accurate, as is the voltage reference, and the 10-bit DAC may be selected quickly.

●The current is as low as 10A in low power consumption mode, and the wake-up time is 30 seconds.

●A wide voltage range of 1.8-5.5V is supported.

●Development may be finished with just one power cord and bottom line, thanks to corresponding development kits and free software tools.

Ⅱ. Market Application of BB5 Series and Comparison with Mainstream MCU

2.1 Market application of BB5 series

The BB5 series of chips are optimized for consumer electronics and industrial embedded applications.

2.1.1 Consumer Electronics

The BB5 series can be found in electronic cigarettes, electric toothbrushes, and other tiny appliances, electric irons, and other small home appliances, hand drills, nail guns, and other tools, as well as small automobiles and other electric toys on the consumer market. SiliconLabs' BB5 family chips may be an excellent choice if you're seeking a low-cost 8-bit MCU solution.

Application of BB5 Series in Consumer Electronics

There are two benefits to going with the BB5 series:

●One goal is to lower BOM expenses. The BB5 family chips can help you save money by removing superfluous components from your system. The voltage regulator, for example, eliminates the need for an external voltage regulator because it includes a reference voltage regulator. Of course, the crystal oscillator, power monitor, and other components that are already built into the device do not need to be expanded.

●The second reason is to conserve the circuit board area. The BB5 series' distinctive "Crossbar" function allows for unprecedented pin flexibility, resulting in a reduced total circuit board.

2.1.2 LED and motor

Ordinary LEDs in large-scale applications such as LED lights and home appliances are another application for the BB5 family. Six independent channels and three complementing channels make up the BB5 series. The LED battery is controlled by the PWM generated. The BB5 series' low power consumption makes it ideal for use as a line power supply or in conjunction with other system components. It can be used to control the motor and switching frequency.

Applications of BB5 Series in LED

2.1.3 Industrial networking

Industrial networking can also benefit from the BB5 series. For example, we require an MCU to gather external temperature, pressure, current, and so on, and then communicate this information to the master node via a small slave node. We thought the BB5 series would be a better fit. It can be manufactured from a small base that attaches to the sensor or it can be included within the sensor itself. This method is more logical and can be used instead of the current MCU method.

Applications of BB5 Series in Industrial Networking

2.2 Comparison with mainstream 8-bit MCU

Let's have a look at how the BB5 series compares to common 8-bit MCUs. I focused on the most commonly used MCUs, such as the N761003, MS51, and STM8. I'm not going to list the STC51 because it's an older chip.

Comparison of BB5 Series with N761003, MS51, STM8

BB5 has a voltage range of 1.71-5.5V, while the other three are closer to 5.5V by more than two points.

STM8 is a unique core that uses ST's STM8 architecture, while the other three are 8051 cores.

Concentrate on the primary frequency. The highest of the three is 24MHz, while BB5 is 50MHz.

BB5 has a flash memory capacity of 32kB, which is higher than the other three.

In terms of crystal error, the BB5 has a 2% crystal error at 50MHz, the MS51 has a 4% crystal error at 24MHz, and the STM8 has a 5% crystal error at 16MHz.

ADC and DAC. BB5 is a 12bit ADC with a conversion speed of 600ksps; MS51 is a 12bit ADC with a conversion speed of 500ksps; STM8 is a 10bit ADC with a conversion speed of 420ksps. BB5 supports 10bit DAC, the other three do not.

Low power consumption mode. BB5 is 50MHz, 30μs wake up; MS51 is 24MHz, 30μs wake up; STM8 is 55μs wake up.

2.3 Comparison with 16-bit and 32-bit MCU

In order to accurately depict the properties of BB5, I compared it to the 16-bit and 32-bit MCUs that were used. BB5 is somewhat ahead of the core clock frequency in general. However, flash and RAM are substantially less powerful than 16-bit and 32-bit processors. The performance of BB5 in terms of ADC is generally comparable to 16-bit and 32-bit.

Comparison of BB5 Series with 16-bit and 32-bit MCU

Ⅲ. Introduction of BB5 Series Development Kit

The BB5 series development kit is available from Silicon Labs. I'm going to introduce one of them, BB52-EK2701A.

Let's look at the BB52-EK2701A development board in more depth.

Development Board BB52-EK2701A

It features a BB52 chip from the BB5 series, which features a 50MHz operating frequency, 32kB flash, 2kB RAM, a user LED, and a button. A J-Link debug connector is supplied in the upper section for debugging the BB52 chip. On both sides, there are several external expansion pins that can be attached to external expansion devices. Hardware devices, such as Qwiic® connectors for connecting the QwiicConnect system's hardware, are also available.

Block Diagram of the Development Board BB52-EK2701A

Then we examine the development board's structure, which comprises the power supply, on-board debug, user LEDs, and buttons.

Provision of electricity The LDO (low dropout regulator), which is an automatic isolation circuit that isolates the LDO when the USB cable is not inserted, adjusts the 5-volt power on the bus to 3.3 volts. The electricity can be injected into the VMCU network from the outside if the USB cable is disconnected and there is no other power supply on the kit.

Power Supply for BB52-EK2701A

You can use the onboard J-Link debug or the external J-Link debug to burn the software. The author is unsure whether this is a normal J-Link. You don't need to acquire another debugger if it supports normal J-Link debug; you can debug it directly with J-Link.

In addition, the development board enables virtual COM with hardware flow control to interface with the BB52 chip's physical serial port. The onboard debug can download programs, update simulations, and send serial data to the BB52 chip via the virtual COM port.