PSRAM is a pseudo SRAM, the internal memory particles are similar to those of SDRAM, but the external interface is different from SDRAM, and does not require the same complex controller and refresh mechanism as SDRAM, the interface of PSRAM is the same as that of SRAM.
PSRAM has evolved from a parallel interface to a serial interface, with SPI, Quad SPI (QPI) and Octal SPI (OPI) serial interfaces for miniaturization applications, providing a wide range of bandwidths from 100Mbps to 2.128Gbps, 8Mb, 16Mb, 32Mb, 64Mb, 128Mb, etc.
In addition to 2G BB SiP, new demand comes from buffer storage of Internet voice streaming data, such as Internet radio, smart voice interaction devices, smart voice interaction robots, wifi speakers, etc. The following are the application areas where the STM32 microcontroller extended IPUS PSRAM is used by IPUS distributors.
Application on mobile printers
In mobile printers, you need to access the cloud through the Internet for relevant data interaction, or you need to do batch ticket printing, hundreds or even thousands of tickets at a time, which requires the terminal to have the ability to cache a certain size of data; some require printing a variety of report formats and diverse requirements for printing fonts, which requires format conversion, font conversion and other operations, requiring a larger amount of RAM to store data. SQPI PSRAM is well suited for such applications, with power saving, small size and suitable capacity compared to parallel port devices.
Application on smart speakers, children’s storytelling machines
Adding PSRAM as a cache for voice data on entry-level smart speakers or storytellers can solve the problem of lagging/intermittent voice playback caused by unstable network connection at the user’s end, or untimely response caused by bandwidth sharing being stuck or a large number of concurrent requests from the cloud, and improve user experience.
By adding ram resources to the system through SQPI PSRAM, the performance of the original product can be significantly improved at the same time, and more complex protocols such as DLNA can be further implemented, and voice wake-up can be realized under Cortex-M3/4 resources to replace key wake-up, which greatly improves the user experience and enhances the product grade.
Display cache for wearable devices
In the recent hot and popular wearable device applications, most mid- to high-end systems use color display, or need to display a larger size, or need a higher resolution, which requires a larger display buffer RAM. The QSPI PSRAM can be used to meet this need.
Application to system OTA online upgrade
In MCU-based related systems, such OTA software upgrades require multiple data transfers due to very limited RAM resources, which brings inconvenience to the upgrade. At this time, if the system comes with 16 ~ 64Mb of SQPI PSRAM, the larger and faster RAM allows data transfer to be done in one go. This is a very good and cost-effective solution for some applications that require frequent automatic software upgrades, simplifying and speeding up the upgrade process, while reducing the redundancy requirement of doubling the Flash capacity of existing solutions.
Application on advanced fingerprint reader
A biometric fingerprint reader, in order to increase detection and recognition speed and improve user experience, needs to capture multiple fingerprint images in one press (usually 50KB size per fingerprint). The system needs to store multiple fingerprint images and perform related image processing. The adoption of SQPI PSRAM optimizes the system design and avoids the embarrassing situation of having to select other unnecessary resources just to choose an MCU with larger on-chip SRAM resources, which would cause the overall BOM cost to increase.
Application in system security protection
One of the elements of system security is to prevent the code from being copied and the system from being stolen and modified. In conventional systems, the program runs in FLASH, and since the content or mask of the Flash is static and unchanging, simple means such as grinding and plate extraction may acquire the running code.
The capacity of IPUS PSRAM products range from 16/32/64Mb, commonly used capacity is 32/64Mb, voltage range is 1.8V/3.3V, standard SPI device, its read and write commands and SPI NOR basically the same, our company Ying Shang Microelectronics can recommend cost-effective and practical products according to the different product needs of customers. We can recommend cost-effective and practical products according to customers’ different product requirements, which can perfectly solve the demand for extra RAM space for smart hardware meeting and achieve the goal of miniaturization and low cost at the same time.
