#!/usr/bin/python3
# vim: fileencoding=utf-8: ts=4: sw=4: expandtab:
#┌────────────────────────────────────────────────────────────────────────────┒
#│      Transfer rate ESP-PSRAM64H  (QPI Read Operations)                     ┃
#┕━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
from matplotlib import pyplot as plt

CLOCK = 84                              # in MHz
MAX = 256                               # in bytes
x,y = [],[]
for i in range(4,MAX+1,4):
    x.append(i//4)                      # x axis in WORDS
    z = 14 + 2*i                        # 14 cycles addr. setup plus two cycles per byte
    y.append(84/z*i)                    # read speed in MB/s

#─────[ Tests ]─────
cyc = 14 + 2*4                          # for 1WORD (4BYTE)
print(f'{84 / cyc * 4:.3f} MB/s')       # 84MHz / cycles * numbytes
cyc = 14 + 2*256                        # for 64WORD (256BYTE)
print(f'{84 / cyc * 256:.3f} MB/s')     # 84MHz / cycles * numbytes

#─────[ Plot ]─────
plt.title('sequential forward reads (WORD size)')
plt.xlabel('WORDS (32bit)')
plt.ylabel('MB/s')
plt.xticks([n for n in range(0,MAX+1,4)])
plt.yticks([n for n in range(0,42+1,2)])
plt.tight_layout()
plt.grid()
plt.plot(x,y)
plt.show()