ST71xx with S29GL512P in STB Application Power On Reset Issue Application Note by Victor Li 1. Introduction The STi71xx family of STMicroelectronics MPEG2/MPEG4 processors is widely used in high definition set top box solutions made in China. STi71xx normally requires NOR flash density of 128 Mbits and up on its EMI as external memory. One of the most common, and easily overlooked, issue with NOR flash applications is Power-On-Reset. Spansion® GL-P products need longer RESET times than the older GL-N serial family. This document uses our customer, Jiuzhou, as a case study to discuss the Power-On-Reset issue when using Spansion’s GL-P products. (Note: Jiuzhou is one of China’s largest STB R&D and manufacturing companies.) 2. Detailed Failure Symptoms Jinzhou’s application uses the ST7167 with our S29GL512P11TFI010. Jinzhou reported that a few units failed STB boot up due to high temperatures, and the failure rate was about 1%. There was no erasing and programming involved, only read operations took place during the system boot up process. As an additional check, Jiuzhou did checksum testing, it was found that checksum testing failed easily at high temperatures. In addition, a scope (Figure 2.1) was used to check the CE#, OE# timing was 270 ns. No access time issue was found. The Reset timing was double checked , when VCC = 2.7V, Reset power was already 2V. The issue seemed to be that there was not enough reset time. Figure 2.1 Scope Screen Shot Publication Number ST71XX_with_S29GL512P_STB_Application_POR_Issues_AN Revision 01 Issue Date July 11, 2011 App l ic atio n No t e Spansion’s GL-P Reset needs the RESET# pin to go low for at least 35 µs when VCC > 2.7V and stable. It was determined that Jiuzhou’s resistor-capacitor (10 kΩ and 0.1 nF) time reset was not enough. Table 2.1 shows the detailed GL-P power-on-reset requirement. Table 2.1 S29GL-P Hardware Reset (RESET#) Operation Parameter JEDEC Std. Description Speed Unit Min 35 µs RESET# Pin Low (NOT During Embedded Algorithms) to Read Mode or Write mode Min 35 µs tRP RESET# Pulse Width Min 35 µs tReady RESET# Pin Low (During Embedded Algorithms) to Read Mode or Write mode tReady tRH Reset High Time Before Read Min 200 ns tRPD RESET# Low to Standby Mode Min 10 µs tRB RY/BY# Recovery Time Min 0 ns Figure 2.2 Reset Timings RY/BY# CE#, OE# tRH RESET# tRP tReady Reset Timings NOT during Embedded Algorithms Reset Timings during Embedded Algorithms tReady RY/BY# tRB CE#, OE# RESET# tRP 3. Correction Action Jiuzhou changed the resistor-capacitor reset parameter to 10 kΩ and 4.7 µF. Retesting at Jiuzhou factory, with the ST7167 with S29GL512P11TFI010 application, found no abnormal results . The Reset timing now matches the GL-P 35 µs requirement. July 11, 2011 ST71XX_with_S29GL512P_STB_Application_POR_Issues_AN_01 2 A pplication 4. Note Conclusion The specification for hardware reset timing and reset current has changed. However, this change has been proven to be of minimal impact on the customers, since many common processors support these parameters. See Table 4.1 for the detailed parameter change. Also, consult the S29GL-P data sheet for advanced information on Hardware Reset Timing for future 65 nm S29GL-R family of products. Table 4.1 Comparison of Hardware Reset Timings Parameter Description JEDEC 3 S29GL-N S29GL-P Std. tREADY RESET# Pin Low (During Embedded Algorithms) to Read or Write Mode 20 ns 35 µs tREADY RESET# Pin Low (NOT During Embedded Algorithms) to Read or Write Mode 500 ns 35 µs tRP RESET# Pulse Width 500 ns 35 µs tRH RESET# High Time Before Read 50 ns 200 ns tRB RY/BY# Recovery Time 0 ns 0 ns 1 µA (Typ) 250 µA (Typ) ICC5 VCC RESET# Current ST71XX_with_S29GL512P_STB_Application_POR_Issues_AN_01 5 µA (Max) July 11, 2011 App l ic atio n No t e 5. Revision History Section Description Revision 01 (July 11, 2011) Initial release July 11, 2011 ST71XX_with_S29GL512P_STB_Application_POR_Issues_AN_01 4 A pplication Note Colophon The products described in this document are designed, developed and manufactured as contemplated for general use, including without limitation, ordinary industrial use, general office use, personal use, and household use, but are not designed, developed and manufactured as contemplated (1) for any use that includes fatal risks or dangers that, unless extremely high safety is secured, could have a serious effect to the public, and could lead directly to death, personal injury, severe physical damage or other loss (i.e., nuclear reaction control in nuclear facility, aircraft flight control, air traffic control, mass transport control, medical life support system, missile launch control in weapon system), or (2) for any use where chance of failure is intolerable (i.e., submersible repeater and artificial satellite). Please note that Spansion will not be liable to you and/or any third party for any claims or damages arising in connection with above-mentioned uses of the products. Any semiconductor devices have an inherent chance of failure. You must protect against injury, damage or loss from such failures by incorporating safety design measures into your facility and equipment such as redundancy, fire protection, and prevention of over-current levels and other abnormal operating conditions. If any products described in this document represent goods or technologies subject to certain restrictions on export under the Foreign Exchange and Foreign Trade Law of Japan, the US Export Administration Regulations or the applicable laws of any other country, the prior authorization by the respective government entity will be required for export of those products. Trademarks and Notice The contents of this document are subject to change without notice. This document may contain information on a Spansion product under development by Spansion. Spansion reserves the right to change or discontinue work on any product without notice. The information in this document is provided as is without warranty or guarantee of any kind as to its accuracy, completeness, operability, fitness for particular purpose, merchantability, non-infringement of third-party rights, or any other warranty, express, implied, or statutory. Spansion assumes no liability for any damages of any kind arising out of the use of the information in this document. Copyright © 2011 Spansion Inc. All rights reserved. Spansion®, the Spansion logo, MirrorBit®, MirrorBit® Eclipse™, ORNAND™, EcoRAM™ and combinations thereof, are trademarks and registered trademarks of Spansion LLC in the United States and other countries. Other names used are for informational purposes only and may be trademarks of their respective owners. 5 ST71XX_with_S29GL512P_STB_Application_POR_Issues_AN_01 July 11, 2011